TY  - CONF
AU  - Cekić, Božidar
AU  - Ivanovski, Valentin
AU  - Codescu, Mirela Maria
AU  - Umićević, Ana
AU  - Ćirić, Katarina
AU  - Manta, Eugen
PY  - 2018
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/12487
AB  - In this paper, it is reported the structural and magnetic properties of Nd13.7Pr0.7Dy0.2Fe73.1Co6.3Ga0.4B5.6 and Nd7.7Pr0.7Dy0.2Fe79.1Co6.3Ga0.4B5.6 magnetic nanocomposites, synthesized by melt-spinning and annealing methods. The Nd-Fe-B ribbons are melt-spun at v=30 m/s in high vacuum and annealed at 715oC for 4 min. in argon. Furthermore, X-ray diffraction and transmission 57Fe Mössbauer spectra at RT are used to investigate the effects of substituent elements: Dy, Pr, Co, Ga on the hard magnetic properties and microstructure of both nanocomposites. Analysis of Mössbauer spectra for Nd13.7Pr0.7Dy0.2Fe73.1Co6.3Ga0.4B5.6 is done in terms of ten Zeeman sextets, one paramagnetic doublet related to Nd1.1Fe4B4 phase and two hyperfine magnetic fields distributions extracted from spectrum. Similar result of analysis of the second nanocomposite is obtained with eleven sextets, one doublet and one distribution. One sextet corresponds to α-Fe phase, while we have identified six iron sextets corresponding to the six distinct iron sites in the Nd2Fe14B structure: 16k1, 16k2, 8j1, 8j2, 4c and 4e. The three remaining sextets belong to Fe3B structure with three inequivalent Fe sites: FeI(8g), FeII(8g) and FeIII(8g). The eleventh sextet of Nd7.7Pr0.7Dy0.2Fe79.1Co6.3Ga0.4B5.6 belongs to FeB. All relevant parameters for both nanocomposites: magnetic hyperfine field, isomer shift and quadrupole splitting are determined for each of these sites. To highlight the thermally induced structural transformations, the quenched samples have been analysed by differential scanning calorimetry and thermo-magnetic measurements. The magnetic properties, measured at RT on the quenched and annealed ribbons, revealed the relationship between the alloy chemical composition and processing.
PB  - Materials Research Forum
C3  - RoPM AM 2017 : 5th International Conference on Powder Metallurgy & Advanced Materials
T1  - Mössbauer spectroscopic analysis of (Nd,Pr,Dy)2(Fe,Co,Ga)14B/α-Fe permanent magnetic nanocomposites
VL  - 8
SP  - 70
EP  - 79
DO  - 10.21741/9781945291999-8
ER  - 

@conference{
author = "Cekić, Božidar and Ivanovski, Valentin and Codescu, Mirela Maria and Umićević, Ana and Ćirić, Katarina and Manta, Eugen",
year = "2018",
abstract = "In this paper, it is reported the structural and magnetic properties of Nd13.7Pr0.7Dy0.2Fe73.1Co6.3Ga0.4B5.6 and Nd7.7Pr0.7Dy0.2Fe79.1Co6.3Ga0.4B5.6 magnetic nanocomposites, synthesized by melt-spinning and annealing methods. The Nd-Fe-B ribbons are melt-spun at v=30 m/s in high vacuum and annealed at 715oC for 4 min. in argon. Furthermore, X-ray diffraction and transmission 57Fe Mössbauer spectra at RT are used to investigate the effects of substituent elements: Dy, Pr, Co, Ga on the hard magnetic properties and microstructure of both nanocomposites. Analysis of Mössbauer spectra for Nd13.7Pr0.7Dy0.2Fe73.1Co6.3Ga0.4B5.6 is done in terms of ten Zeeman sextets, one paramagnetic doublet related to Nd1.1Fe4B4 phase and two hyperfine magnetic fields distributions extracted from spectrum. Similar result of analysis of the second nanocomposite is obtained with eleven sextets, one doublet and one distribution. One sextet corresponds to α-Fe phase, while we have identified six iron sextets corresponding to the six distinct iron sites in the Nd2Fe14B structure: 16k1, 16k2, 8j1, 8j2, 4c and 4e. The three remaining sextets belong to Fe3B structure with three inequivalent Fe sites: FeI(8g), FeII(8g) and FeIII(8g). The eleventh sextet of Nd7.7Pr0.7Dy0.2Fe79.1Co6.3Ga0.4B5.6 belongs to FeB. All relevant parameters for both nanocomposites: magnetic hyperfine field, isomer shift and quadrupole splitting are determined for each of these sites. To highlight the thermally induced structural transformations, the quenched samples have been analysed by differential scanning calorimetry and thermo-magnetic measurements. The magnetic properties, measured at RT on the quenched and annealed ribbons, revealed the relationship between the alloy chemical composition and processing.",
publisher = "Materials Research Forum",
journal = "RoPM AM 2017 : 5th International Conference on Powder Metallurgy & Advanced Materials",
title = "Mössbauer spectroscopic analysis of (Nd,Pr,Dy)2(Fe,Co,Ga)14B/α-Fe permanent magnetic nanocomposites",
volume = "8",
pages = "70-79",
doi = "10.21741/9781945291999-8"
}

Cekić, B., Ivanovski, V., Codescu, M. M., Umićević, A., Ćirić, K.,& Manta, E.. (2018). Mössbauer spectroscopic analysis of (Nd,Pr,Dy)2(Fe,Co,Ga)14B/α-Fe permanent magnetic nanocomposites. in RoPM AM 2017 : 5th International Conference on Powder Metallurgy & Advanced Materials
Materials Research Forum., 8, 70-79.
https://doi.org/10.21741/9781945291999-8

Cekić B, Ivanovski V, Codescu MM, Umićević A, Ćirić K, Manta E. Mössbauer spectroscopic analysis of (Nd,Pr,Dy)2(Fe,Co,Ga)14B/α-Fe permanent magnetic nanocomposites. in RoPM AM 2017 : 5th International Conference on Powder Metallurgy & Advanced Materials. 2018;8:70-79.
doi:10.21741/9781945291999-8 .

Cekić, Božidar, Ivanovski, Valentin, Codescu, Mirela Maria, Umićević, Ana, Ćirić, Katarina, Manta, Eugen, "Mössbauer spectroscopic analysis of (Nd,Pr,Dy)2(Fe,Co,Ga)14B/α-Fe permanent magnetic nanocomposites" in RoPM AM 2017 : 5th International Conference on Powder Metallurgy & Advanced Materials, 8 (2018):70-79,
https://doi.org/10.21741/9781945291999-8 . .

TY  - JOUR
AU  - Umićević, Ana
AU  - Mahnke, Heinz-Eberhard
AU  - Belošević-Čavor, Jelena
AU  - Cekić, Božidar Đ.
AU  - Schumacher, Gerhard
AU  - Mađarević, Ivan
AU  - Koteski, Vasil J.
PY  - 2016
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/7091
AB  - X-ray absorption spectroscopy is employed to investigate site preference and lattice relaxation around Mo, Ru, Hf, W and Re dopants in Ni3Al. The site occupation preference and the measured distances between the refractory elements as dopants and the nearest host atoms are compared with the results of ab initio calculations within the density functional theory. Combined experimental and theoretical results indicate that Mo, Hf, W and Re atoms reside on the Al sublattice in Ni3Al, while Ru atoms occupy the Ni sublattice. A more pronounced lattice relaxation was detected in the case of Hf and Ru doping, with a strong outward relaxation of the nearest Ni and Al atoms.
T2  - Journal of Synchrotron Radiation
T1  - Site preference and lattice relaxation around 4d and 5d refractory elements in Ni3Al
VL  - 23
SP  - 286
EP  - 292
DO  - 10.1107/S1600577515020688
ER  - 

@article{
author = "Umićević, Ana and Mahnke, Heinz-Eberhard and Belošević-Čavor, Jelena and Cekić, Božidar Đ. and Schumacher, Gerhard and Mađarević, Ivan and Koteski, Vasil J.",
year = "2016",
abstract = "X-ray absorption spectroscopy is employed to investigate site preference and lattice relaxation around Mo, Ru, Hf, W and Re dopants in Ni3Al. The site occupation preference and the measured distances between the refractory elements as dopants and the nearest host atoms are compared with the results of ab initio calculations within the density functional theory. Combined experimental and theoretical results indicate that Mo, Hf, W and Re atoms reside on the Al sublattice in Ni3Al, while Ru atoms occupy the Ni sublattice. A more pronounced lattice relaxation was detected in the case of Hf and Ru doping, with a strong outward relaxation of the nearest Ni and Al atoms.",
journal = "Journal of Synchrotron Radiation",
title = "Site preference and lattice relaxation around 4d and 5d refractory elements in Ni3Al",
volume = "23",
pages = "286-292",
doi = "10.1107/S1600577515020688"
}

Umićević, A., Mahnke, H., Belošević-Čavor, J., Cekić, B. Đ., Schumacher, G., Mađarević, I.,& Koteski, V. J.. (2016). Site preference and lattice relaxation around 4d and 5d refractory elements in Ni3Al. in Journal of Synchrotron Radiation, 23, 286-292.
https://doi.org/10.1107/S1600577515020688

Umićević A, Mahnke H, Belošević-Čavor J, Cekić BĐ, Schumacher G, Mađarević I, Koteski VJ. Site preference and lattice relaxation around 4d and 5d refractory elements in Ni3Al. in Journal of Synchrotron Radiation. 2016;23:286-292.
doi:10.1107/S1600577515020688 .

Umićević, Ana, Mahnke, Heinz-Eberhard, Belošević-Čavor, Jelena, Cekić, Božidar Đ., Schumacher, Gerhard, Mađarević, Ivan, Koteski, Vasil J., "Site preference and lattice relaxation around 4d and 5d refractory elements in Ni3Al" in Journal of Synchrotron Radiation, 23 (2016):286-292,
https://doi.org/10.1107/S1600577515020688 . .

TY  - JOUR
AU  - Ivanovski, Valentin N.
AU  - Cekić, Božidar Đ.
AU  - Umićević, Ana
AU  - Barudžija, Tanja
AU  - Schumacher, G.
AU  - Mađarević, Ivan
AU  - Koteski, Vasil J.
PY  - 2015
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/249
AB  - Perturbed angular correlation measurements of the hyperfine interactions of the Ta-181 probe in the polycrystalline intermetallic Ni3Al doped with 0.5 and 5 at.% Hf were performed in the temperature range 78-1230 K. The observed local hyperfine fields at the Hf-181/Ta-181 probe showed that Hf atoms are substituting on Al sites in the L1(2) structure of Ni3Al. The two minor electric quadrupole interactions that were found for each Ni3Al alloy are discussed taking into account the L1(2) cubic structure and its two tetragonal distortions: D0(22) and L6(0). The presence of two tetragonal transformations of the parent cubic L1(2) lattice in 0.5 at.% Hf and 5 at.% Hf doped Ni3Al was revealed by X-ray diffraction. The ab initio calculations, performed with the projector augmented wave method correctly reproduce the experimental results and enable discussion on the structural and electronic properties of the polycrystalline alloys. The experimental and theoretical investigations showed that hafnium additions prefer aluminum sites in Ni3Al. (C) 2014 Elsevier B.V. All rights reserved.
T2  - Journal of Alloys and Compounds
T1  - Site preference of Hf dopant in Ni3Al alloys: A perturbed angular correlation study
VL  - 622
SP  - 541
EP  - 547
DO  - 10.1016/j.jallcom.2014.10.132
ER  - 

@article{
author = "Ivanovski, Valentin N. and Cekić, Božidar Đ. and Umićević, Ana and Barudžija, Tanja and Schumacher, G. and Mađarević, Ivan and Koteski, Vasil J.",
year = "2015",
abstract = "Perturbed angular correlation measurements of the hyperfine interactions of the Ta-181 probe in the polycrystalline intermetallic Ni3Al doped with 0.5 and 5 at.% Hf were performed in the temperature range 78-1230 K. The observed local hyperfine fields at the Hf-181/Ta-181 probe showed that Hf atoms are substituting on Al sites in the L1(2) structure of Ni3Al. The two minor electric quadrupole interactions that were found for each Ni3Al alloy are discussed taking into account the L1(2) cubic structure and its two tetragonal distortions: D0(22) and L6(0). The presence of two tetragonal transformations of the parent cubic L1(2) lattice in 0.5 at.% Hf and 5 at.% Hf doped Ni3Al was revealed by X-ray diffraction. The ab initio calculations, performed with the projector augmented wave method correctly reproduce the experimental results and enable discussion on the structural and electronic properties of the polycrystalline alloys. The experimental and theoretical investigations showed that hafnium additions prefer aluminum sites in Ni3Al. (C) 2014 Elsevier B.V. All rights reserved.",
journal = "Journal of Alloys and Compounds",
title = "Site preference of Hf dopant in Ni3Al alloys: A perturbed angular correlation study",
volume = "622",
pages = "541-547",
doi = "10.1016/j.jallcom.2014.10.132"
}

Ivanovski, V. N., Cekić, B. Đ., Umićević, A., Barudžija, T., Schumacher, G., Mađarević, I.,& Koteski, V. J.. (2015). Site preference of Hf dopant in Ni3Al alloys: A perturbed angular correlation study. in Journal of Alloys and Compounds, 622, 541-547.
https://doi.org/10.1016/j.jallcom.2014.10.132

Ivanovski VN, Cekić BĐ, Umićević A, Barudžija T, Schumacher G, Mađarević I, Koteski VJ. Site preference of Hf dopant in Ni3Al alloys: A perturbed angular correlation study. in Journal of Alloys and Compounds. 2015;622:541-547.
doi:10.1016/j.jallcom.2014.10.132 .

Ivanovski, Valentin N., Cekić, Božidar Đ., Umićević, Ana, Barudžija, Tanja, Schumacher, G., Mađarević, Ivan, Koteski, Vasil J., "Site preference of Hf dopant in Ni3Al alloys: A perturbed angular correlation study" in Journal of Alloys and Compounds, 622 (2015):541-547,
https://doi.org/10.1016/j.jallcom.2014.10.132 . .

TY  - JOUR
AU  - Ivanovski, Valentin N.
AU  - Umićević, Ana
AU  - Belošević-Čavor, Jelena
AU  - Lei, Hechang
AU  - Li, Lijun
AU  - Cekić, Božidar Đ.
AU  - Koteski, Vasil J.
AU  - Petrović, Čedomir
PY  - 2015
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/749
AB  - The local electronic and magnetic structure, hyperfine interactions, and phase composition of polycrystalline Ni-deficient Ni3-xFexAl (x = 0.18 and 0.36) were investigated by means of Fe-57 Mossbauer spectroscopy. The samples were characterized by X-ray diffraction and magnetization measurements. The ab initio calculations performed with the projector augmented wave method and the calculations of the energies of iron point defects were done to elucidate the electronic structure and site preference of Fe doped Ni3Al. The value of calculated electric field gradient tensor V-zz = 1.6 10(21) Vm(-2) matches well with the results of Mossbauer spectroscopy and indicates that the Fe atoms occupy Ni sites. (C) 2015 Elsevier B.V. All rights reserved.
T2  - Journal of Alloys and Compounds
T1  - Local structure study of Fe dopants in Ni-deficit Ni3Al alloys
VL  - 651
SP  - 705
EP  - 711
DO  - 10.1016/j.jallcom.2015.08.171
ER  - 

@article{
author = "Ivanovski, Valentin N. and Umićević, Ana and Belošević-Čavor, Jelena and Lei, Hechang and Li, Lijun and Cekić, Božidar Đ. and Koteski, Vasil J. and Petrović, Čedomir",
year = "2015",
abstract = "The local electronic and magnetic structure, hyperfine interactions, and phase composition of polycrystalline Ni-deficient Ni3-xFexAl (x = 0.18 and 0.36) were investigated by means of Fe-57 Mossbauer spectroscopy. The samples were characterized by X-ray diffraction and magnetization measurements. The ab initio calculations performed with the projector augmented wave method and the calculations of the energies of iron point defects were done to elucidate the electronic structure and site preference of Fe doped Ni3Al. The value of calculated electric field gradient tensor V-zz = 1.6 10(21) Vm(-2) matches well with the results of Mossbauer spectroscopy and indicates that the Fe atoms occupy Ni sites. (C) 2015 Elsevier B.V. All rights reserved.",
journal = "Journal of Alloys and Compounds",
title = "Local structure study of Fe dopants in Ni-deficit Ni3Al alloys",
volume = "651",
pages = "705-711",
doi = "10.1016/j.jallcom.2015.08.171"
}

Ivanovski, V. N., Umićević, A., Belošević-Čavor, J., Lei, H., Li, L., Cekić, B. Đ., Koteski, V. J.,& Petrović, Č.. (2015). Local structure study of Fe dopants in Ni-deficit Ni3Al alloys. in Journal of Alloys and Compounds, 651, 705-711.
https://doi.org/10.1016/j.jallcom.2015.08.171

Ivanovski VN, Umićević A, Belošević-Čavor J, Lei H, Li L, Cekić BĐ, Koteski VJ, Petrović Č. Local structure study of Fe dopants in Ni-deficit Ni3Al alloys. in Journal of Alloys and Compounds. 2015;651:705-711.
doi:10.1016/j.jallcom.2015.08.171 .

Ivanovski, Valentin N., Umićević, Ana, Belošević-Čavor, Jelena, Lei, Hechang, Li, Lijun, Cekić, Božidar Đ., Koteski, Vasil J., Petrović, Čedomir, "Local structure study of Fe dopants in Ni-deficit Ni3Al alloys" in Journal of Alloys and Compounds, 651 (2015):705-711,
https://doi.org/10.1016/j.jallcom.2015.08.171 . .

TY  - JOUR
AU  - Umićević, Ana
AU  - Cekić, Božidar Đ.
AU  - Belošević-Čavor, Jelena
AU  - Koteski, Vasil J.
AU  - Papendorf, Benjamin
AU  - Riedel, Ralf
AU  - Ionescu, Emanuel
PY  - 2015
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/185
AB  - The evolution of the environment of Hf sites in a hafnium-alkoxide-modified polysilsesquioxane upon polymer-to-ceramic transformation was investigated via the perturbed angular correlation (PAC) method. The results of the PAC measurements on samples thermally treated at temperatures from 400 to 1300 degrees C indicate that Hf is surrounded only by oxygen at all studied temperatures. This finding is in agreement with the evolution pathway of polymer-derived SiHfOC ceramics, which were reported to be generated as single-phase amorphous materials upon pyrolysis of alkoxide-modified polysiloxanes and subsequently to phase separate and crystallize towards HfO2/SiOC nanocomposites. Thus, the results presented here support our previous statement that there is a thermodynamic control on the phase separation and crystallization behavior of Si-M-O-C (M = metal) ceramics (Ionescu et al. 96;2013:1899-1903), which in the case of Hf leads to the precipitation and crystallization of hafnia nanoparticles within a SiOC matrix. (C) 2014 Elsevier Ltd. All rights reserved.
T2  - Journal of the European Ceramic Society
T1  - Evolution of the local structure at Hf sites in SiHfOC upon ceramization of a hafnium-alkoxide-modified polysilsesquioxane: A perturbed angular correlation study
VL  - 35
IS  - 1
SP  - 29
EP  - 35
DO  - 10.1016/j.jeurceramsoc.2014.08.023
ER  - 

@article{
author = "Umićević, Ana and Cekić, Božidar Đ. and Belošević-Čavor, Jelena and Koteski, Vasil J. and Papendorf, Benjamin and Riedel, Ralf and Ionescu, Emanuel",
year = "2015",
abstract = "The evolution of the environment of Hf sites in a hafnium-alkoxide-modified polysilsesquioxane upon polymer-to-ceramic transformation was investigated via the perturbed angular correlation (PAC) method. The results of the PAC measurements on samples thermally treated at temperatures from 400 to 1300 degrees C indicate that Hf is surrounded only by oxygen at all studied temperatures. This finding is in agreement with the evolution pathway of polymer-derived SiHfOC ceramics, which were reported to be generated as single-phase amorphous materials upon pyrolysis of alkoxide-modified polysiloxanes and subsequently to phase separate and crystallize towards HfO2/SiOC nanocomposites. Thus, the results presented here support our previous statement that there is a thermodynamic control on the phase separation and crystallization behavior of Si-M-O-C (M = metal) ceramics (Ionescu et al. 96;2013:1899-1903), which in the case of Hf leads to the precipitation and crystallization of hafnia nanoparticles within a SiOC matrix. (C) 2014 Elsevier Ltd. All rights reserved.",
journal = "Journal of the European Ceramic Society",
title = "Evolution of the local structure at Hf sites in SiHfOC upon ceramization of a hafnium-alkoxide-modified polysilsesquioxane: A perturbed angular correlation study",
volume = "35",
number = "1",
pages = "29-35",
doi = "10.1016/j.jeurceramsoc.2014.08.023"
}

Umićević, A., Cekić, B. Đ., Belošević-Čavor, J., Koteski, V. J., Papendorf, B., Riedel, R.,& Ionescu, E.. (2015). Evolution of the local structure at Hf sites in SiHfOC upon ceramization of a hafnium-alkoxide-modified polysilsesquioxane: A perturbed angular correlation study. in Journal of the European Ceramic Society, 35(1), 29-35.
https://doi.org/10.1016/j.jeurceramsoc.2014.08.023

Umićević A, Cekić BĐ, Belošević-Čavor J, Koteski VJ, Papendorf B, Riedel R, Ionescu E. Evolution of the local structure at Hf sites in SiHfOC upon ceramization of a hafnium-alkoxide-modified polysilsesquioxane: A perturbed angular correlation study. in Journal of the European Ceramic Society. 2015;35(1):29-35.
doi:10.1016/j.jeurceramsoc.2014.08.023 .

Umićević, Ana, Cekić, Božidar Đ., Belošević-Čavor, Jelena, Koteski, Vasil J., Papendorf, Benjamin, Riedel, Ralf, Ionescu, Emanuel, "Evolution of the local structure at Hf sites in SiHfOC upon ceramization of a hafnium-alkoxide-modified polysilsesquioxane: A perturbed angular correlation study" in Journal of the European Ceramic Society, 35, no. 1 (2015):29-35,
https://doi.org/10.1016/j.jeurceramsoc.2014.08.023 . .

TY  - JOUR
AU  - Lazarević, Zorica Ž.
AU  - Jovalekić, Čedomir
AU  - Ivanovski, Valentin N.
AU  - Recnik, Aleksander
AU  - Milutinovic, Aleksandra
AU  - Cekić, Božidar Đ.
AU  - Romčević, Nebojša Ž.
PY  - 2014
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/6009
AB  - ZnFe2O4 was prepared by a soft mechanochemical route from two starting combinations of powders: (1) Zn(OH)(2)/alpha-Fe2O3 and (2) Zn(OH)(2)/Fe(OH)(3) mixed in a planetary ball mill. The mechanochemical treatment provoked reaction leading to the formation of the ZnFe2O4 spinel phase that was monitored by XRD, TEM, IR and Raman spectroscopy. The spinel phase was first observed after 4 h of milling and its formation was completed after 18 h in both the cases of starting precursors. The synthesized ZnFe2O4 has a nanocrystalline structure with a crystallite size of about 20.3 and 17.6 nm, for the cases (1) and (2), respectively. In the far-infrared reflectivity spectra are seen four active modes. Raman spectra suggest an existence of mixed spinel structure in the obtained nanosamples. In order to confirm phase formation and cation arrangement, Mossbauer measurements were done. Estimated degree of inversion is about 0.58 for both starting mixtures. The magnetic properties of the prepared ZnFe2O4 powders were also studied. The results show that the samples have a typical superparamagnetic-like behavior at room temperature. Higher values of magnetization in the case of samples obtained with starting mixture (2) suggest somewhat higher degree of cation inversion. (C) 2014 Elsevier Ltd. All rights reserved.
T2  - Journal of Physics and Chemistry of Solids
T1  - Characterization of partially inverse spinel ZnFe2O4 with high saturation magnetization synthesized via soft mechanochemically assisted route
VL  - 75
IS  - 7
SP  - 869
EP  - 877
DO  - 10.1016/j.jpcs.2014.03.004
ER  - 

@article{
author = "Lazarević, Zorica Ž. and Jovalekić, Čedomir and Ivanovski, Valentin N. and Recnik, Aleksander and Milutinovic, Aleksandra and Cekić, Božidar Đ. and Romčević, Nebojša Ž.",
year = "2014",
abstract = "ZnFe2O4 was prepared by a soft mechanochemical route from two starting combinations of powders: (1) Zn(OH)(2)/alpha-Fe2O3 and (2) Zn(OH)(2)/Fe(OH)(3) mixed in a planetary ball mill. The mechanochemical treatment provoked reaction leading to the formation of the ZnFe2O4 spinel phase that was monitored by XRD, TEM, IR and Raman spectroscopy. The spinel phase was first observed after 4 h of milling and its formation was completed after 18 h in both the cases of starting precursors. The synthesized ZnFe2O4 has a nanocrystalline structure with a crystallite size of about 20.3 and 17.6 nm, for the cases (1) and (2), respectively. In the far-infrared reflectivity spectra are seen four active modes. Raman spectra suggest an existence of mixed spinel structure in the obtained nanosamples. In order to confirm phase formation and cation arrangement, Mossbauer measurements were done. Estimated degree of inversion is about 0.58 for both starting mixtures. The magnetic properties of the prepared ZnFe2O4 powders were also studied. The results show that the samples have a typical superparamagnetic-like behavior at room temperature. Higher values of magnetization in the case of samples obtained with starting mixture (2) suggest somewhat higher degree of cation inversion. (C) 2014 Elsevier Ltd. All rights reserved.",
journal = "Journal of Physics and Chemistry of Solids",
title = "Characterization of partially inverse spinel ZnFe2O4 with high saturation magnetization synthesized via soft mechanochemically assisted route",
volume = "75",
number = "7",
pages = "869-877",
doi = "10.1016/j.jpcs.2014.03.004"
}

Lazarević, Z. Ž., Jovalekić, Č., Ivanovski, V. N., Recnik, A., Milutinovic, A., Cekić, B. Đ.,& Romčević, N. Ž.. (2014). Characterization of partially inverse spinel ZnFe2O4 with high saturation magnetization synthesized via soft mechanochemically assisted route. in Journal of Physics and Chemistry of Solids, 75(7), 869-877.
https://doi.org/10.1016/j.jpcs.2014.03.004

Lazarević ZŽ, Jovalekić Č, Ivanovski VN, Recnik A, Milutinovic A, Cekić BĐ, Romčević NŽ. Characterization of partially inverse spinel ZnFe2O4 with high saturation magnetization synthesized via soft mechanochemically assisted route. in Journal of Physics and Chemistry of Solids. 2014;75(7):869-877.
doi:10.1016/j.jpcs.2014.03.004 .

Lazarević, Zorica Ž., Jovalekić, Čedomir, Ivanovski, Valentin N., Recnik, Aleksander, Milutinovic, Aleksandra, Cekić, Božidar Đ., Romčević, Nebojša Ž., "Characterization of partially inverse spinel ZnFe2O4 with high saturation magnetization synthesized via soft mechanochemically assisted route" in Journal of Physics and Chemistry of Solids, 75, no. 7 (2014):869-877,
https://doi.org/10.1016/j.jpcs.2014.03.004 . .

TY  - JOUR
AU  - Lazarević, Zorica Ž.
AU  - Jovalekic, C.
AU  - Recnik, A.
AU  - Ivanovski, Valentin N.
AU  - Milutinovic, A.
AU  - Romčević, Maja J.
AU  - Pavlović, Miodrag B.
AU  - Cekić, Božidar Đ.
AU  - Romčević, Nebojša Ž.
PY  - 2013
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/5357
AB  - Nickel ferrite, NiFe2O4 has been prepared by a soft mechanochemical route from mixture of (1) Ni(OH)(2) and alpha-Fe2O3 and (2) Ni(OH)(2) and Fe(OH)(3) powders in a planetary ball mill for varying duration. Soft mechanochemical reaction leading to formation of the NiFe2O4 spinel phase was followed by X-ray diffraction, Raman and infrared spectroscopy, TGA, scanning and transmission microscopy. The spinel phase formation was first observed after 4 h of milling and its formation was completed after 25 h in the both cases. The synthesized NiFe2O4 ferrite has a nanocrystalline structure with a crystallite size of about 20 and 10 nm respectively for the cases (1) and (2). The final grain size in the system (1) is about twice as large as that in the system (2), what is a consequence of different reaction paths in these two processing routes. There are five Raman and four IR active modes. Mossbauer spectroscopy studies implied on the possible cation distribution between the tetrahedral and octahedral sites in formed NiFe2O4 spinel structure. We were able to estimate the degree of inversion at most 0.82 in the case (1) and 0.66 in the case (2). (c) 2012 Elsevier Ltd. All rights reserved.
T2  - Materials Research Bulletin
T1  - Preparation and characterization of spinel nickel ferrite obtained by the soft mechanochemically assisted synthesis
VL  - 48
IS  - 2
SP  - 404
EP  - 415
DO  - 10.1016/j.materresbull.2012.10.061
ER  - 

@article{
author = "Lazarević, Zorica Ž. and Jovalekic, C. and Recnik, A. and Ivanovski, Valentin N. and Milutinovic, A. and Romčević, Maja J. and Pavlović, Miodrag B. and Cekić, Božidar Đ. and Romčević, Nebojša Ž.",
year = "2013",
abstract = "Nickel ferrite, NiFe2O4 has been prepared by a soft mechanochemical route from mixture of (1) Ni(OH)(2) and alpha-Fe2O3 and (2) Ni(OH)(2) and Fe(OH)(3) powders in a planetary ball mill for varying duration. Soft mechanochemical reaction leading to formation of the NiFe2O4 spinel phase was followed by X-ray diffraction, Raman and infrared spectroscopy, TGA, scanning and transmission microscopy. The spinel phase formation was first observed after 4 h of milling and its formation was completed after 25 h in the both cases. The synthesized NiFe2O4 ferrite has a nanocrystalline structure with a crystallite size of about 20 and 10 nm respectively for the cases (1) and (2). The final grain size in the system (1) is about twice as large as that in the system (2), what is a consequence of different reaction paths in these two processing routes. There are five Raman and four IR active modes. Mossbauer spectroscopy studies implied on the possible cation distribution between the tetrahedral and octahedral sites in formed NiFe2O4 spinel structure. We were able to estimate the degree of inversion at most 0.82 in the case (1) and 0.66 in the case (2). (c) 2012 Elsevier Ltd. All rights reserved.",
journal = "Materials Research Bulletin",
title = "Preparation and characterization of spinel nickel ferrite obtained by the soft mechanochemically assisted synthesis",
volume = "48",
number = "2",
pages = "404-415",
doi = "10.1016/j.materresbull.2012.10.061"
}

Lazarević, Z. Ž., Jovalekic, C., Recnik, A., Ivanovski, V. N., Milutinovic, A., Romčević, M. J., Pavlović, M. B., Cekić, B. Đ.,& Romčević, N. Ž.. (2013). Preparation and characterization of spinel nickel ferrite obtained by the soft mechanochemically assisted synthesis. in Materials Research Bulletin, 48(2), 404-415.
https://doi.org/10.1016/j.materresbull.2012.10.061

Lazarević ZŽ, Jovalekic C, Recnik A, Ivanovski VN, Milutinovic A, Romčević MJ, Pavlović MB, Cekić BĐ, Romčević NŽ. Preparation and characterization of spinel nickel ferrite obtained by the soft mechanochemically assisted synthesis. in Materials Research Bulletin. 2013;48(2):404-415.
doi:10.1016/j.materresbull.2012.10.061 .

Lazarević, Zorica Ž., Jovalekic, C., Recnik, A., Ivanovski, Valentin N., Milutinovic, A., Romčević, Maja J., Pavlović, Miodrag B., Cekić, Božidar Đ., Romčević, Nebojša Ž., "Preparation and characterization of spinel nickel ferrite obtained by the soft mechanochemically assisted synthesis" in Materials Research Bulletin, 48, no. 2 (2013):404-415,
https://doi.org/10.1016/j.materresbull.2012.10.061 . .

TY  - JOUR
AU  - Lazarević, Zorica Ž.
AU  - Jovalekić, Čedomir
AU  - Milutinovic, A.
AU  - Sekulić, Dalibor L.
AU  - Ivanovski, Valentin N.
AU  - Recnik, A.
AU  - Cekić, Božidar Đ.
AU  - Romčević, Nebojša Ž.
PY  - 2013
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/7003
AB  - NiFe2O4 and ZnFe2O4 ferrites have been prepared by soft mechanochemical synthesis. The formation of spinel phase and crystal structure of sintered powders were analyzed by X-ray diffraction, Raman spectroscopy, and transmission microscopy. In order to confirm phase formation and cation arrangement, Mossbauer measurements were done. Investigation of the magnetization as a function of magnetic field confirms an expected change of the degree of inversion in the spinel structure with the sintering. The electrical DC/resistivity/conductivity was measured in the temperature range of 298-423 K. Impedance spectroscopy was performed in the wide frequency range (100 Hz-10 MHz) at different temperatures. (C) 2 013 AIP Publishing LLC
T2  - Journal of Applied Physics
T1  - Nanodimensional spinel NiFe2O4 and ZnFe2O4 ferrites prepared by soft mechanochemical synthesis
VL  - 113
IS  - 18
DO  - 10.1063/1.4801962
ER  - 

@article{
author = "Lazarević, Zorica Ž. and Jovalekić, Čedomir and Milutinovic, A. and Sekulić, Dalibor L. and Ivanovski, Valentin N. and Recnik, A. and Cekić, Božidar Đ. and Romčević, Nebojša Ž.",
year = "2013",
abstract = "NiFe2O4 and ZnFe2O4 ferrites have been prepared by soft mechanochemical synthesis. The formation of spinel phase and crystal structure of sintered powders were analyzed by X-ray diffraction, Raman spectroscopy, and transmission microscopy. In order to confirm phase formation and cation arrangement, Mossbauer measurements were done. Investigation of the magnetization as a function of magnetic field confirms an expected change of the degree of inversion in the spinel structure with the sintering. The electrical DC/resistivity/conductivity was measured in the temperature range of 298-423 K. Impedance spectroscopy was performed in the wide frequency range (100 Hz-10 MHz) at different temperatures. (C) 2 013 AIP Publishing LLC",
journal = "Journal of Applied Physics",
title = "Nanodimensional spinel NiFe2O4 and ZnFe2O4 ferrites prepared by soft mechanochemical synthesis",
volume = "113",
number = "18",
doi = "10.1063/1.4801962"
}

Lazarević, Z. Ž., Jovalekić, Č., Milutinovic, A., Sekulić, D. L., Ivanovski, V. N., Recnik, A., Cekić, B. Đ.,& Romčević, N. Ž.. (2013). Nanodimensional spinel NiFe2O4 and ZnFe2O4 ferrites prepared by soft mechanochemical synthesis. in Journal of Applied Physics, 113(18).
https://doi.org/10.1063/1.4801962

Lazarević ZŽ, Jovalekić Č, Milutinovic A, Sekulić DL, Ivanovski VN, Recnik A, Cekić BĐ, Romčević NŽ. Nanodimensional spinel NiFe2O4 and ZnFe2O4 ferrites prepared by soft mechanochemical synthesis. in Journal of Applied Physics. 2013;113(18).
doi:10.1063/1.4801962 .

Lazarević, Zorica Ž., Jovalekić, Čedomir, Milutinovic, A., Sekulić, Dalibor L., Ivanovski, Valentin N., Recnik, A., Cekić, Božidar Đ., Romčević, Nebojša Ž., "Nanodimensional spinel NiFe2O4 and ZnFe2O4 ferrites prepared by soft mechanochemical synthesis" in Journal of Applied Physics, 113, no. 18 (2013),
https://doi.org/10.1063/1.4801962 . .

TY  - JOUR
AU  - Ivanovski, Valentin N.
AU  - Cekić, Božidar Đ.
AU  - Umićević, Ana
AU  - Belošević-Čavor, Jelena
AU  - Schumacher, G.
AU  - Koteski, Vasil J.
AU  - Barudžija, Tanja
PY  - 2013
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/5625
AB  - The Time Differential Perturbed Angular (TDPAC) measurements of nuclear quadrupole interactions (NQIs) at Ta-181 ion probe in the polycrystalline intermetallic alloy gamma-Ni3Al doped with 0.2 at. % Hf were performed in the temperature range 78-1230K, in order to determine the lattice location of Hf atoms in the ordered gamma-Ni3Al structure. The two NQIs obtained are discussed within the present L1(2) cubic structure and a tetragonal distortion of L1(2) to another two DO22 and L6(0) type structures. The first low frequency NQI at the site of the Ta-181 ion-probe after substitution of aluminum for hafnium in DO22 at ambient temperature, is v(Q1)(300 K) = 39(1) MHz with eta(1) = 0. The corresponding high frequency value on the second crystallographic site in L6(0), is v(Q2)(300 K) = 204(14) MHz with eta(2) = 0.47(11). These two NQIs have different temperature behavior. The presence of both DO22 and L6(0) tetragonal distortions of the parent cubic L1(2) lattice, detected after adding 0.2 at. % Hf, are with modulations to the lattice constant (a) with a ratio (c/a), 2.04 and 0.87, respectively. Ab initio calculations of electronic and structural properties and hyperfine parameters at the Ta-181 ion probe of the gamma-Ni3Al-0.2 at. % Hf alloy were performed using the full potential augmented plane wave plus local-orbital (APW+lo) method as implemented in the WIEN2k code. The accuracy of the calculations and comparison with the experimental results enabled us to identify the observed hyperfine interactions and to infer the EFG sign that cannot be measured in conventional TDPAC measurements. (C) 2013 AIP Publishing LLC.
T2  - Journal of Applied Physics
T1  - Hf dopants in gamma -Ni3Al alloy
VL  - 114
IS  - 6
DO  - 10.1063/1.4818317
ER  - 

@article{
author = "Ivanovski, Valentin N. and Cekić, Božidar Đ. and Umićević, Ana and Belošević-Čavor, Jelena and Schumacher, G. and Koteski, Vasil J. and Barudžija, Tanja",
year = "2013",
abstract = "The Time Differential Perturbed Angular (TDPAC) measurements of nuclear quadrupole interactions (NQIs) at Ta-181 ion probe in the polycrystalline intermetallic alloy gamma-Ni3Al doped with 0.2 at. % Hf were performed in the temperature range 78-1230K, in order to determine the lattice location of Hf atoms in the ordered gamma-Ni3Al structure. The two NQIs obtained are discussed within the present L1(2) cubic structure and a tetragonal distortion of L1(2) to another two DO22 and L6(0) type structures. The first low frequency NQI at the site of the Ta-181 ion-probe after substitution of aluminum for hafnium in DO22 at ambient temperature, is v(Q1)(300 K) = 39(1) MHz with eta(1) = 0. The corresponding high frequency value on the second crystallographic site in L6(0), is v(Q2)(300 K) = 204(14) MHz with eta(2) = 0.47(11). These two NQIs have different temperature behavior. The presence of both DO22 and L6(0) tetragonal distortions of the parent cubic L1(2) lattice, detected after adding 0.2 at. % Hf, are with modulations to the lattice constant (a) with a ratio (c/a), 2.04 and 0.87, respectively. Ab initio calculations of electronic and structural properties and hyperfine parameters at the Ta-181 ion probe of the gamma-Ni3Al-0.2 at. % Hf alloy were performed using the full potential augmented plane wave plus local-orbital (APW+lo) method as implemented in the WIEN2k code. The accuracy of the calculations and comparison with the experimental results enabled us to identify the observed hyperfine interactions and to infer the EFG sign that cannot be measured in conventional TDPAC measurements. (C) 2013 AIP Publishing LLC.",
journal = "Journal of Applied Physics",
title = "Hf dopants in gamma -Ni3Al alloy",
volume = "114",
number = "6",
doi = "10.1063/1.4818317"
}

Ivanovski, V. N., Cekić, B. Đ., Umićević, A., Belošević-Čavor, J., Schumacher, G., Koteski, V. J.,& Barudžija, T.. (2013). Hf dopants in gamma -Ni3Al alloy. in Journal of Applied Physics, 114(6).
https://doi.org/10.1063/1.4818317

Ivanovski VN, Cekić BĐ, Umićević A, Belošević-Čavor J, Schumacher G, Koteski VJ, Barudžija T. Hf dopants in gamma -Ni3Al alloy. in Journal of Applied Physics. 2013;114(6).
doi:10.1063/1.4818317 .

Ivanovski, Valentin N., Cekić, Božidar Đ., Umićević, Ana, Belošević-Čavor, Jelena, Schumacher, G., Koteski, Vasil J., Barudžija, Tanja, "Hf dopants in gamma -Ni3Al alloy" in Journal of Applied Physics, 114, no. 6 (2013),
https://doi.org/10.1063/1.4818317 . .

TY  - JOUR
AU  - Cekić, Božidar Đ.
AU  - Ćirić, Katarina D.
AU  - Iordoc, Mihail
AU  - Marković, Smilja
AU  - Mitrić, Miodrag
AU  - Stojić, Dragica Lj.
PY  - 2013
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/5386
AB  - The kinetics of hydrogen absorption in Zr-based alloys Zr-2.5Nb, Zr-10Nb, Zr-2.5Nb-3Ta and Zr-10Nb-12Ta have been investigated in the temperature range 673-973 K at 1 bar hydrogen pressure. The improvement in hydrogen kinetics and a slight decrease of maximal amount of hydrogen absorbed were observed upon cycling. The rate determining steps are as follows: geometrical contraction for all samples except Zr-10Nb-12Ta; diffusion in the beginning for Zr-10Nb at 973 K Zr-2.5Nb-3Ta at 673 K and 973 K; first order reaction Zr-10Nb-12Ta at all temperatures. The amount of additives, Nb and Ta, is found to have major influence on the mechanism of the absorption process.
T2  - Journal of Alloys and Compounds
T1  - Kinetics of hydrogen absorption in Zr-based alloys
VL  - 559
SP  - 162
EP  - 166
DO  - 10.1016/j.jallcom.2013.01.104
ER  - 

@article{
author = "Cekić, Božidar Đ. and Ćirić, Katarina D. and Iordoc, Mihail and Marković, Smilja and Mitrić, Miodrag and Stojić, Dragica Lj.",
year = "2013",
abstract = "The kinetics of hydrogen absorption in Zr-based alloys Zr-2.5Nb, Zr-10Nb, Zr-2.5Nb-3Ta and Zr-10Nb-12Ta have been investigated in the temperature range 673-973 K at 1 bar hydrogen pressure. The improvement in hydrogen kinetics and a slight decrease of maximal amount of hydrogen absorbed were observed upon cycling. The rate determining steps are as follows: geometrical contraction for all samples except Zr-10Nb-12Ta; diffusion in the beginning for Zr-10Nb at 973 K Zr-2.5Nb-3Ta at 673 K and 973 K; first order reaction Zr-10Nb-12Ta at all temperatures. The amount of additives, Nb and Ta, is found to have major influence on the mechanism of the absorption process.",
journal = "Journal of Alloys and Compounds",
title = "Kinetics of hydrogen absorption in Zr-based alloys",
volume = "559",
pages = "162-166",
doi = "10.1016/j.jallcom.2013.01.104"
}

Cekić, B. Đ., Ćirić, K. D., Iordoc, M., Marković, S., Mitrić, M.,& Stojić, D. Lj.. (2013). Kinetics of hydrogen absorption in Zr-based alloys. in Journal of Alloys and Compounds, 559, 162-166.
https://doi.org/10.1016/j.jallcom.2013.01.104

Cekić BĐ, Ćirić KD, Iordoc M, Marković S, Mitrić M, Stojić DL. Kinetics of hydrogen absorption in Zr-based alloys. in Journal of Alloys and Compounds. 2013;559:162-166.
doi:10.1016/j.jallcom.2013.01.104 .

Cekić, Božidar Đ., Ćirić, Katarina D., Iordoc, Mihail, Marković, Smilja, Mitrić, Miodrag, Stojić, Dragica Lj., "Kinetics of hydrogen absorption in Zr-based alloys" in Journal of Alloys and Compounds, 559 (2013):162-166,
https://doi.org/10.1016/j.jallcom.2013.01.104 . .

TY  - JOUR
AU  - Lei, Hechang
AU  - Božin, Emil S.
AU  - Llobet, A.
AU  - Ivanovski, Valentin N.
AU  - Koteski, Vasil J.
AU  - Belošević-Čavor, Jelena
AU  - Cekić, Božidar Đ.
AU  - Petrović, Čedomir
PY  - 2012
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/5040
AB  - We report the evolution of structural and magnetic properties in La2O3(Fe1-xMnx)(2)Se-2. Heat capacity and bulk magnetization indicate an increased ferromagnetic component of the long-range magnetic order and possible increased degree of frustration. Atomic disorder on Fe(Mn) sites suppresses the temperature of the long-range order whereas intermediate alloys show a rich magnetic phase diagram.
T2  - Physical Review B: Condensed Matter and Materials Physics
T1  - Magnetism in La2O3(Fe1-xMnx)(2)Se-2 tuned by Fe/Mn ratio
VL  - 86
IS  - 12
DO  - 10.1103/PhysRevB.86.125122
ER  - 

@article{
author = "Lei, Hechang and Božin, Emil S. and Llobet, A. and Ivanovski, Valentin N. and Koteski, Vasil J. and Belošević-Čavor, Jelena and Cekić, Božidar Đ. and Petrović, Čedomir",
year = "2012",
abstract = "We report the evolution of structural and magnetic properties in La2O3(Fe1-xMnx)(2)Se-2. Heat capacity and bulk magnetization indicate an increased ferromagnetic component of the long-range magnetic order and possible increased degree of frustration. Atomic disorder on Fe(Mn) sites suppresses the temperature of the long-range order whereas intermediate alloys show a rich magnetic phase diagram.",
journal = "Physical Review B: Condensed Matter and Materials Physics",
title = "Magnetism in La2O3(Fe1-xMnx)(2)Se-2 tuned by Fe/Mn ratio",
volume = "86",
number = "12",
doi = "10.1103/PhysRevB.86.125122"
}

Lei, H., Božin, E. S., Llobet, A., Ivanovski, V. N., Koteski, V. J., Belošević-Čavor, J., Cekić, B. Đ.,& Petrović, Č.. (2012). Magnetism in La2O3(Fe1-xMnx)(2)Se-2 tuned by Fe/Mn ratio. in Physical Review B: Condensed Matter and Materials Physics, 86(12).
https://doi.org/10.1103/PhysRevB.86.125122

Lei H, Božin ES, Llobet A, Ivanovski VN, Koteski VJ, Belošević-Čavor J, Cekić BĐ, Petrović Č. Magnetism in La2O3(Fe1-xMnx)(2)Se-2 tuned by Fe/Mn ratio. in Physical Review B: Condensed Matter and Materials Physics. 2012;86(12).
doi:10.1103/PhysRevB.86.125122 .

Lei, Hechang, Božin, Emil S., Llobet, A., Ivanovski, Valentin N., Koteski, Vasil J., Belošević-Čavor, Jelena, Cekić, Božidar Đ., Petrović, Čedomir, "Magnetism in La2O3(Fe1-xMnx)(2)Se-2 tuned by Fe/Mn ratio" in Physical Review B: Condensed Matter and Materials Physics, 86, no. 12 (2012),
https://doi.org/10.1103/PhysRevB.86.125122 . .

TY  - JOUR
AU  - Cekić, Božidar Đ.
AU  - Umićević, Ana
AU  - Ivanovski, Valentin N.
AU  - Hu, Rongwei
AU  - Petrovic, Cedomir
AU  - David, Bohumil
AU  - Barudžija, Tanja
PY  - 2012
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/4925
AB  - The perturbed angular correlation method was employed to study the temperature dependence of electric field gradients at the Ta-181 probe in the polycrystalline Hf2Ni7 compound. The temperature evolution of the sample content was measured using high-temperature X-ray diffraction. To check the magnetic order of the sample, magnetization measurements and additional perturbed angular correlation measurements with externally applied magnetic field were performed. All obtained spectra showed no evidence of magnetic order of the Hf2Ni7 phase. Within the experimental resolution of the apparatus, the measured electric field gradients at Ta-181 probe for the two inequivalent Hf-181/Ta-181 sites in the Hf2Ni7 compound appeared as one in the range of 78-944 K. A single quadrupole interaction implies that the electric field gradients at the two Hf sites must be quite similar. At 293 K, the measured quadrupole interaction parameters are v(Q) = 433(1) MHz and eta = 0.300(4). An increase of the quadrupole frequency and a gradual rising of the asymmetry parameter were observed with increasing temperature. The high-temperature X-ray diffraction indicated a build up of HfO2 above 693 K.
T2  - Nuclear technology and radiation protection
T1  - Perturbed Angular Correlation Investigation of the Electric Field Gradient At Ta-181 Probe in the Hf2ni7 Compound
VL  - 27
IS  - 2
SP  - 95
EP  - 102
DO  - 10.2298/NTRP1202095C
ER  - 

@article{
author = "Cekić, Božidar Đ. and Umićević, Ana and Ivanovski, Valentin N. and Hu, Rongwei and Petrovic, Cedomir and David, Bohumil and Barudžija, Tanja",
year = "2012",
abstract = "The perturbed angular correlation method was employed to study the temperature dependence of electric field gradients at the Ta-181 probe in the polycrystalline Hf2Ni7 compound. The temperature evolution of the sample content was measured using high-temperature X-ray diffraction. To check the magnetic order of the sample, magnetization measurements and additional perturbed angular correlation measurements with externally applied magnetic field were performed. All obtained spectra showed no evidence of magnetic order of the Hf2Ni7 phase. Within the experimental resolution of the apparatus, the measured electric field gradients at Ta-181 probe for the two inequivalent Hf-181/Ta-181 sites in the Hf2Ni7 compound appeared as one in the range of 78-944 K. A single quadrupole interaction implies that the electric field gradients at the two Hf sites must be quite similar. At 293 K, the measured quadrupole interaction parameters are v(Q) = 433(1) MHz and eta = 0.300(4). An increase of the quadrupole frequency and a gradual rising of the asymmetry parameter were observed with increasing temperature. The high-temperature X-ray diffraction indicated a build up of HfO2 above 693 K.",
journal = "Nuclear technology and radiation protection",
title = "Perturbed Angular Correlation Investigation of the Electric Field Gradient At Ta-181 Probe in the Hf2ni7 Compound",
volume = "27",
number = "2",
pages = "95-102",
doi = "10.2298/NTRP1202095C"
}

Cekić, B. Đ., Umićević, A., Ivanovski, V. N., Hu, R., Petrovic, C., David, B.,& Barudžija, T.. (2012). Perturbed Angular Correlation Investigation of the Electric Field Gradient At Ta-181 Probe in the Hf2ni7 Compound. in Nuclear technology and radiation protection, 27(2), 95-102.
https://doi.org/10.2298/NTRP1202095C

Cekić BĐ, Umićević A, Ivanovski VN, Hu R, Petrovic C, David B, Barudžija T. Perturbed Angular Correlation Investigation of the Electric Field Gradient At Ta-181 Probe in the Hf2ni7 Compound. in Nuclear technology and radiation protection. 2012;27(2):95-102.
doi:10.2298/NTRP1202095C .

Cekić, Božidar Đ., Umićević, Ana, Ivanovski, Valentin N., Hu, Rongwei, Petrovic, Cedomir, David, Bohumil, Barudžija, Tanja, "Perturbed Angular Correlation Investigation of the Electric Field Gradient At Ta-181 Probe in the Hf2ni7 Compound" in Nuclear technology and radiation protection, 27, no. 2 (2012):95-102,
https://doi.org/10.2298/NTRP1202095C . .

TY  - JOUR
AU  - Cekić, Božidar Đ.
AU  - Ivanovski, Valentin N.
AU  - Đorđević, Aleksandar N.
AU  - Aleksić, Velimir
AU  - Tomić, Zorica
AU  - Bogdanović, Stefan
AU  - Umićević, Ana
PY  - 2012
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/4927
AB  - The paper addresses the issue of health risk associated with the presence of chrysotile in the soil type ranker formed on massive serpentines occurring in the area of Bubanj Potok, a settlement located in the southern Belgrade environs, Serbia. Characterization of the ranker soil was conducted by scanning electron microscopy, X-ray diffraction, micro-Raman spectroscopy and transmission Fe-57 Mossbauer spectroscopy. Scanning electron microscopy figures showed regular shaped smectite (montmorillonite) particles, aggregates of chlorite, and elongated sheets of serpentines minerals antigorite. X-ray diffraction analysis confirmed the presence of detrital mineral quartz polymorph as well as minor amounts of other mineral species. Micro-Raman spectroscopy identified the presence of dominant minerals, such as montmorillonite, kaolinite, muscovite, gypsum, calcite, albite, amphiboles (hornblende/kaersutite) and orthoclase. Important polymorph silica modifications of quartz, olivine (forsterite), pyroxene (enstatite/ferrosilite, diopside/hedenbergite), and serpentine (antigorite/lizardite/chrysotile) were identified.
T2  - Nuclear technology and radiation protection
T1  - Mineral Characterization of Soil Type Ranker Formed on Serpentines Occurring in Southern Belgrade Environs Bubanj Potok
VL  - 27
IS  - 2
SP  - 131
EP  - 136
DO  - 10.2298/NTRP1202131C
ER  - 

@article{
author = "Cekić, Božidar Đ. and Ivanovski, Valentin N. and Đorđević, Aleksandar N. and Aleksić, Velimir and Tomić, Zorica and Bogdanović, Stefan and Umićević, Ana",
year = "2012",
abstract = "The paper addresses the issue of health risk associated with the presence of chrysotile in the soil type ranker formed on massive serpentines occurring in the area of Bubanj Potok, a settlement located in the southern Belgrade environs, Serbia. Characterization of the ranker soil was conducted by scanning electron microscopy, X-ray diffraction, micro-Raman spectroscopy and transmission Fe-57 Mossbauer spectroscopy. Scanning electron microscopy figures showed regular shaped smectite (montmorillonite) particles, aggregates of chlorite, and elongated sheets of serpentines minerals antigorite. X-ray diffraction analysis confirmed the presence of detrital mineral quartz polymorph as well as minor amounts of other mineral species. Micro-Raman spectroscopy identified the presence of dominant minerals, such as montmorillonite, kaolinite, muscovite, gypsum, calcite, albite, amphiboles (hornblende/kaersutite) and orthoclase. Important polymorph silica modifications of quartz, olivine (forsterite), pyroxene (enstatite/ferrosilite, diopside/hedenbergite), and serpentine (antigorite/lizardite/chrysotile) were identified.",
journal = "Nuclear technology and radiation protection",
title = "Mineral Characterization of Soil Type Ranker Formed on Serpentines Occurring in Southern Belgrade Environs Bubanj Potok",
volume = "27",
number = "2",
pages = "131-136",
doi = "10.2298/NTRP1202131C"
}

Cekić, B. Đ., Ivanovski, V. N., Đorđević, A. N., Aleksić, V., Tomić, Z., Bogdanović, S.,& Umićević, A.. (2012). Mineral Characterization of Soil Type Ranker Formed on Serpentines Occurring in Southern Belgrade Environs Bubanj Potok. in Nuclear technology and radiation protection, 27(2), 131-136.
https://doi.org/10.2298/NTRP1202131C

Cekić BĐ, Ivanovski VN, Đorđević AN, Aleksić V, Tomić Z, Bogdanović S, Umićević A. Mineral Characterization of Soil Type Ranker Formed on Serpentines Occurring in Southern Belgrade Environs Bubanj Potok. in Nuclear technology and radiation protection. 2012;27(2):131-136.
doi:10.2298/NTRP1202131C .

Cekić, Božidar Đ., Ivanovski, Valentin N., Đorđević, Aleksandar N., Aleksić, Velimir, Tomić, Zorica, Bogdanović, Stefan, Umićević, Ana, "Mineral Characterization of Soil Type Ranker Formed on Serpentines Occurring in Southern Belgrade Environs Bubanj Potok" in Nuclear technology and radiation protection, 27, no. 2 (2012):131-136,
https://doi.org/10.2298/NTRP1202131C . .

TY  - JOUR
AU  - Lei, Hechang
AU  - Ryu, Hyejin
AU  - Ivanovski, Valentin N.
AU  - Warren, J. B.
AU  - Frenkel, A. I.
AU  - Cekić, Božidar Đ.
AU  - Yin, Wei-Guo
AU  - Petrović, Čedomir
PY  - 2012
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/5176
AB  - We have successfully synthesized a layered iron oxychalcogenide BaFe2Se2O single crystal. This compound is built up of Ba and Fe-Se(O) layers alternatively stacked along the c axis. The Fe-Se(O) layers contain double chains of edge-shared Fe-Se(O) tetrahedra that propagate along the b axis and are bridged by oxygen along the a axis. Physical property measurements indicate that BaFe2Se2O is a semiconductor without the Curie-Weiss behavior up to 350 K. There is a possible long-range antiferromagnetic transition at 240 K, corresponding to the peak in specific-heat measurement, and two transitions at 115 K and 43 K where magnetic susceptibility drops abruptly. The magnetic entropy up to 300 K is much smaller than the expected value for Fe2+ in tetrahedral crystal fields and the Mossbauer spectrum indicates that long-range magnetic order is unlikely at 294 K. Our results suggest that BaFe2Se2O is a magnetic insulator at the borderline between a long-range antiferromagnetic spin ordering and possible spin dimerization.
T2  - Physical Review B: Condensed Matter and Materials Physics
T1  - Structure and physical properties of the layered iron oxychalcogenide BaFe2Se2O
VL  - 86
IS  - 19
DO  - 10.1103/PhysRevB.86.195133
ER  - 

@article{
author = "Lei, Hechang and Ryu, Hyejin and Ivanovski, Valentin N. and Warren, J. B. and Frenkel, A. I. and Cekić, Božidar Đ. and Yin, Wei-Guo and Petrović, Čedomir",
year = "2012",
abstract = "We have successfully synthesized a layered iron oxychalcogenide BaFe2Se2O single crystal. This compound is built up of Ba and Fe-Se(O) layers alternatively stacked along the c axis. The Fe-Se(O) layers contain double chains of edge-shared Fe-Se(O) tetrahedra that propagate along the b axis and are bridged by oxygen along the a axis. Physical property measurements indicate that BaFe2Se2O is a semiconductor without the Curie-Weiss behavior up to 350 K. There is a possible long-range antiferromagnetic transition at 240 K, corresponding to the peak in specific-heat measurement, and two transitions at 115 K and 43 K where magnetic susceptibility drops abruptly. The magnetic entropy up to 300 K is much smaller than the expected value for Fe2+ in tetrahedral crystal fields and the Mossbauer spectrum indicates that long-range magnetic order is unlikely at 294 K. Our results suggest that BaFe2Se2O is a magnetic insulator at the borderline between a long-range antiferromagnetic spin ordering and possible spin dimerization.",
journal = "Physical Review B: Condensed Matter and Materials Physics",
title = "Structure and physical properties of the layered iron oxychalcogenide BaFe2Se2O",
volume = "86",
number = "19",
doi = "10.1103/PhysRevB.86.195133"
}

Lei, H., Ryu, H., Ivanovski, V. N., Warren, J. B., Frenkel, A. I., Cekić, B. Đ., Yin, W.,& Petrović, Č.. (2012). Structure and physical properties of the layered iron oxychalcogenide BaFe2Se2O. in Physical Review B: Condensed Matter and Materials Physics, 86(19).
https://doi.org/10.1103/PhysRevB.86.195133

Lei H, Ryu H, Ivanovski VN, Warren JB, Frenkel AI, Cekić BĐ, Yin W, Petrović Č. Structure and physical properties of the layered iron oxychalcogenide BaFe2Se2O. in Physical Review B: Condensed Matter and Materials Physics. 2012;86(19).
doi:10.1103/PhysRevB.86.195133 .

Lei, Hechang, Ryu, Hyejin, Ivanovski, Valentin N., Warren, J. B., Frenkel, A. I., Cekić, Božidar Đ., Yin, Wei-Guo, Petrović, Čedomir, "Structure and physical properties of the layered iron oxychalcogenide BaFe2Se2O" in Physical Review B: Condensed Matter and Materials Physics, 86, no. 19 (2012),
https://doi.org/10.1103/PhysRevB.86.195133 . .

TY  - JOUR
AU  - Lazarević, Zorica Ž.
AU  - Jovalekić, Čedomir
AU  - Recnik, A.
AU  - Ivanovski, Valentin N.
AU  - Mitrić, Miodrag
AU  - Romčević, Maja J.
AU  - Paunović, Novica M.
AU  - Cekić, Božidar Đ.
AU  - Romčević, Nebojša Ž.
PY  - 2011
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/4525
AB  - Manganese ferrite, MnFe2O4 have been prepared by a soft mechanochemical route from mixture of (a) Mn(OH)(2) and alpha-Fe2O3 and (b) Mn(OH)(2) and Fe(OH)(3) powders in a planetary ball mill. The mixture was activated for varying duration. Soft mechanochemical reaction leading to formation of the MnFe2O4 spinel phase was followed by X-ray diffraction, Raman spectroscopy, scanning and transmission microscopy and magnetization measurements. The spinel phase formation was first observed after 12 h of milling and its formation was completed after 25 h in both cases. The synthesized MnFe2O4 ferrite has a nanocrystalline structure with a crystallite size of about 40 and 50 nm respectively for cases (a) and (b). There are five Raman active modes. Measurements after 25 h of milling show magnetization values of 70.4 emu/g and 71.1 emu/g respectively for cases (a) and (b). In order to understand better the whole process of phase formation, Mossbauer measurements were done. (C) 2011 Elsevier B.V. All rights reserved.
T2  - Journal of Alloys and Compounds
T1  - Study of manganese ferrite powders prepared by a soft mechanochemical route
VL  - 509
IS  - 41
SP  - 9977
EP  - 9985
DO  - 10.1016/j.jallcom.2011.08.004
ER  - 

@article{
author = "Lazarević, Zorica Ž. and Jovalekić, Čedomir and Recnik, A. and Ivanovski, Valentin N. and Mitrić, Miodrag and Romčević, Maja J. and Paunović, Novica M. and Cekić, Božidar Đ. and Romčević, Nebojša Ž.",
year = "2011",
abstract = "Manganese ferrite, MnFe2O4 have been prepared by a soft mechanochemical route from mixture of (a) Mn(OH)(2) and alpha-Fe2O3 and (b) Mn(OH)(2) and Fe(OH)(3) powders in a planetary ball mill. The mixture was activated for varying duration. Soft mechanochemical reaction leading to formation of the MnFe2O4 spinel phase was followed by X-ray diffraction, Raman spectroscopy, scanning and transmission microscopy and magnetization measurements. The spinel phase formation was first observed after 12 h of milling and its formation was completed after 25 h in both cases. The synthesized MnFe2O4 ferrite has a nanocrystalline structure with a crystallite size of about 40 and 50 nm respectively for cases (a) and (b). There are five Raman active modes. Measurements after 25 h of milling show magnetization values of 70.4 emu/g and 71.1 emu/g respectively for cases (a) and (b). In order to understand better the whole process of phase formation, Mossbauer measurements were done. (C) 2011 Elsevier B.V. All rights reserved.",
journal = "Journal of Alloys and Compounds",
title = "Study of manganese ferrite powders prepared by a soft mechanochemical route",
volume = "509",
number = "41",
pages = "9977-9985",
doi = "10.1016/j.jallcom.2011.08.004"
}

Lazarević, Z. Ž., Jovalekić, Č., Recnik, A., Ivanovski, V. N., Mitrić, M., Romčević, M. J., Paunović, N. M., Cekić, B. Đ.,& Romčević, N. Ž.. (2011). Study of manganese ferrite powders prepared by a soft mechanochemical route. in Journal of Alloys and Compounds, 509(41), 9977-9985.
https://doi.org/10.1016/j.jallcom.2011.08.004

Lazarević ZŽ, Jovalekić Č, Recnik A, Ivanovski VN, Mitrić M, Romčević MJ, Paunović NM, Cekić BĐ, Romčević NŽ. Study of manganese ferrite powders prepared by a soft mechanochemical route. in Journal of Alloys and Compounds. 2011;509(41):9977-9985.
doi:10.1016/j.jallcom.2011.08.004 .

Lazarević, Zorica Ž., Jovalekić, Čedomir, Recnik, A., Ivanovski, Valentin N., Mitrić, Miodrag, Romčević, Maja J., Paunović, Novica M., Cekić, Božidar Đ., Romčević, Nebojša Ž., "Study of manganese ferrite powders prepared by a soft mechanochemical route" in Journal of Alloys and Compounds, 509, no. 41 (2011):9977-9985,
https://doi.org/10.1016/j.jallcom.2011.08.004 . .

TY  - JOUR
AU  - Cekić, Božidar Đ.
AU  - Ivanovski, Valentin N.
AU  - Zak, T.
AU  - Stojić, Dragica Lj.
AU  - Belošević-Čavor, Jelena
AU  - Koteski, Vasil J.
AU  - Umićević, Ana
PY  - 2011
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/4410
AB  - Mossbauer spectrum measured on ferromagnetic HfFe2 at 296 K, consists of four six-line components and one doublet. The Laves phase HfFe2 has three kinds of crystal structures: cubic MgCu2(C15), hexagonal MgZn2(C14) and MgNi2(C36). We assigned two sextets to the 2a and 6h sites of C14, one to the C15 and the fourth sextet to the minor presence of alpha-Fe. The doublet originates from small amount of FeO, apparently a corrosion product. The pseudobinary compound of Hf0.75Ta0.25Fe2 (C14) undergoes the first - order transition to antiferromagnetic (AFM) state at about 180 K due to the strong spin fluctuation. Therefore, a magnetic sextet and a doublet were observed for the spectra assigned to the 6h and 2a site. The second sextet is attached to the minor presence of Fe3O4.
T2  - Romanian Journal of Physics
T1  - Mössbauer Study of HfFe2 and Hf0.75Ta0.25Fe2
VL  - 56
IS  - 5-6
SP  - 719
EP  - 723
UR  - https://hdl.handle.net/21.15107/rcub_vinar_4410
ER  - 

@article{
author = "Cekić, Božidar Đ. and Ivanovski, Valentin N. and Zak, T. and Stojić, Dragica Lj. and Belošević-Čavor, Jelena and Koteski, Vasil J. and Umićević, Ana",
year = "2011",
abstract = "Mossbauer spectrum measured on ferromagnetic HfFe2 at 296 K, consists of four six-line components and one doublet. The Laves phase HfFe2 has three kinds of crystal structures: cubic MgCu2(C15), hexagonal MgZn2(C14) and MgNi2(C36). We assigned two sextets to the 2a and 6h sites of C14, one to the C15 and the fourth sextet to the minor presence of alpha-Fe. The doublet originates from small amount of FeO, apparently a corrosion product. The pseudobinary compound of Hf0.75Ta0.25Fe2 (C14) undergoes the first - order transition to antiferromagnetic (AFM) state at about 180 K due to the strong spin fluctuation. Therefore, a magnetic sextet and a doublet were observed for the spectra assigned to the 6h and 2a site. The second sextet is attached to the minor presence of Fe3O4.",
journal = "Romanian Journal of Physics",
title = "Mössbauer Study of HfFe2 and Hf0.75Ta0.25Fe2",
volume = "56",
number = "5-6",
pages = "719-723",
url = "https://hdl.handle.net/21.15107/rcub_vinar_4410"
}

Cekić, B. Đ., Ivanovski, V. N., Zak, T., Stojić, D. Lj., Belošević-Čavor, J., Koteski, V. J.,& Umićević, A.. (2011). Mössbauer Study of HfFe2 and Hf0.75Ta0.25Fe2. in Romanian Journal of Physics, 56(5-6), 719-723.
https://hdl.handle.net/21.15107/rcub_vinar_4410

Cekić BĐ, Ivanovski VN, Zak T, Stojić DL, Belošević-Čavor J, Koteski VJ, Umićević A. Mössbauer Study of HfFe2 and Hf0.75Ta0.25Fe2. in Romanian Journal of Physics. 2011;56(5-6):719-723.
https://hdl.handle.net/21.15107/rcub_vinar_4410 .

Cekić, Božidar Đ., Ivanovski, Valentin N., Zak, T., Stojić, Dragica Lj., Belošević-Čavor, Jelena, Koteski, Vasil J., Umićević, Ana, "Mössbauer Study of HfFe2 and Hf0.75Ta0.25Fe2" in Romanian Journal of Physics, 56, no. 5-6 (2011):719-723,
https://hdl.handle.net/21.15107/rcub_vinar_4410 .

TY  - JOUR
AU  - Jugović, Dragana
AU  - Mitrić, Miodrag
AU  - Kuzmanović, Maja D.
AU  - Cvjetićanin, Nikola
AU  - Škapin, Srečo Davor
AU  - Cekić, Božidar Đ.
AU  - Ivanovski, Valentin N.
AU  - Uskoković, Dragan
PY  - 2011
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/4261
AB  - The olivine type LiFePO4 is synthesized via a simple and inexpensive route by aqueous co-precipitation of an Fe(II) precursor material in molten stearic acid and subsequent heat treatment at different temperatures. Stearic acid serves as both chelating agent and carbonaceous material. The obtained composites with carbon are characterized by X-ray powder diffraction, field emission scanning electron microscopy, and Mossbauer spectroscopy. Electrochemical characteristics of the composites are evaluated by using galvanostatic charge/discharge tests. The powder obtained at 700 degrees C delivers discharge capacity of 160 mAh g(-1), quite near the theoretical value. (C) 2011 Elsevier B.V. All rights reserved.
T2  - Journal of Power Sources
T1  - Preparation of LiFePO4/C composites by co-precipitation in molten stearic acid
VL  - 196
IS  - 10
SP  - 4613
EP  - 4618
DO  - 10.1016/j.jpowsour.2011.01.072
ER  - 

@article{
author = "Jugović, Dragana and Mitrić, Miodrag and Kuzmanović, Maja D. and Cvjetićanin, Nikola and Škapin, Srečo Davor and Cekić, Božidar Đ. and Ivanovski, Valentin N. and Uskoković, Dragan",
year = "2011",
abstract = "The olivine type LiFePO4 is synthesized via a simple and inexpensive route by aqueous co-precipitation of an Fe(II) precursor material in molten stearic acid and subsequent heat treatment at different temperatures. Stearic acid serves as both chelating agent and carbonaceous material. The obtained composites with carbon are characterized by X-ray powder diffraction, field emission scanning electron microscopy, and Mossbauer spectroscopy. Electrochemical characteristics of the composites are evaluated by using galvanostatic charge/discharge tests. The powder obtained at 700 degrees C delivers discharge capacity of 160 mAh g(-1), quite near the theoretical value. (C) 2011 Elsevier B.V. All rights reserved.",
journal = "Journal of Power Sources",
title = "Preparation of LiFePO4/C composites by co-precipitation in molten stearic acid",
volume = "196",
number = "10",
pages = "4613-4618",
doi = "10.1016/j.jpowsour.2011.01.072"
}

Jugović, D., Mitrić, M., Kuzmanović, M. D., Cvjetićanin, N., Škapin, S. D., Cekić, B. Đ., Ivanovski, V. N.,& Uskoković, D.. (2011). Preparation of LiFePO4/C composites by co-precipitation in molten stearic acid. in Journal of Power Sources, 196(10), 4613-4618.
https://doi.org/10.1016/j.jpowsour.2011.01.072

Jugović D, Mitrić M, Kuzmanović MD, Cvjetićanin N, Škapin SD, Cekić BĐ, Ivanovski VN, Uskoković D. Preparation of LiFePO4/C composites by co-precipitation in molten stearic acid. in Journal of Power Sources. 2011;196(10):4613-4618.
doi:10.1016/j.jpowsour.2011.01.072 .

Jugović, Dragana, Mitrić, Miodrag, Kuzmanović, Maja D., Cvjetićanin, Nikola, Škapin, Srečo Davor, Cekić, Božidar Đ., Ivanovski, Valentin N., Uskoković, Dragan, "Preparation of LiFePO4/C composites by co-precipitation in molten stearic acid" in Journal of Power Sources, 196, no. 10 (2011):4613-4618,
https://doi.org/10.1016/j.jpowsour.2011.01.072 . .

TY  - CONF
AU  - Cekić, Božidar Đ.
AU  - Ivanovski, Valentin N.
AU  - Codescu, Mirela
AU  - Umićević, Ana
AU  - Barudžija, Tanja
AU  - Patroi, Eros
PY  - 2011
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/6914
AB  - Among novel magnetic intermetallics based on rare earth-transition compounds, the Nd2Fe14B/alpha-Fe isotropic nanocomposites have been obtained by recrystallization from an amorphous phase, prepared by melt spinning. For variable 5 wt.% Fe and 10 wt.% Fe contents we recorded transmission Fe-57 Mossbauer spectra at the room temperature, hardened of the alpha-Fe phase by exchange interactions. The spectra have been analyzed in terms of ten Zeeman sextets and one paramagnetic doublet related to the Nd1.1Fe4B4 phase. One sextet corresponds to the alpha-Fe phase, whereas others are attributed to six non-equivalent Fe sites in the Nd2Fe14B structure, namely 16k(1), 16k(2), 8j(1), 8j(2), 4c, and 4e. The three remaining sextets belong to the Fe3B structure with three inequivalent Fe sites Fe-I(8g), Fe-II(8g) and Fe-III(8g). All relevant parameters for both nanocomposites: the magnetic hyperfine field, the isomer shift and the quadrupole splitting are determined for each of these sites.
C3  - Solid State Phenomena
T1  - Mossbauer spectroscopic analysis of Nd2Fe14B/alpha-Fe hard magnetic nanocomposites
VL  - 170
SP  - 154
EP  - 159
DO  - 10.4028/www.scientific.net/SSP.170.154
ER  - 

@conference{
author = "Cekić, Božidar Đ. and Ivanovski, Valentin N. and Codescu, Mirela and Umićević, Ana and Barudžija, Tanja and Patroi, Eros",
year = "2011",
abstract = "Among novel magnetic intermetallics based on rare earth-transition compounds, the Nd2Fe14B/alpha-Fe isotropic nanocomposites have been obtained by recrystallization from an amorphous phase, prepared by melt spinning. For variable 5 wt.% Fe and 10 wt.% Fe contents we recorded transmission Fe-57 Mossbauer spectra at the room temperature, hardened of the alpha-Fe phase by exchange interactions. The spectra have been analyzed in terms of ten Zeeman sextets and one paramagnetic doublet related to the Nd1.1Fe4B4 phase. One sextet corresponds to the alpha-Fe phase, whereas others are attributed to six non-equivalent Fe sites in the Nd2Fe14B structure, namely 16k(1), 16k(2), 8j(1), 8j(2), 4c, and 4e. The three remaining sextets belong to the Fe3B structure with three inequivalent Fe sites Fe-I(8g), Fe-II(8g) and Fe-III(8g). All relevant parameters for both nanocomposites: the magnetic hyperfine field, the isomer shift and the quadrupole splitting are determined for each of these sites.",
journal = "Solid State Phenomena",
title = "Mossbauer spectroscopic analysis of Nd2Fe14B/alpha-Fe hard magnetic nanocomposites",
volume = "170",
pages = "154-159",
doi = "10.4028/www.scientific.net/SSP.170.154"
}

Cekić, B. Đ., Ivanovski, V. N., Codescu, M., Umićević, A., Barudžija, T.,& Patroi, E.. (2011). Mossbauer spectroscopic analysis of Nd2Fe14B/alpha-Fe hard magnetic nanocomposites. in Solid State Phenomena, 170, 154-159.
https://doi.org/10.4028/www.scientific.net/SSP.170.154

Cekić BĐ, Ivanovski VN, Codescu M, Umićević A, Barudžija T, Patroi E. Mossbauer spectroscopic analysis of Nd2Fe14B/alpha-Fe hard magnetic nanocomposites. in Solid State Phenomena. 2011;170:154-159.
doi:10.4028/www.scientific.net/SSP.170.154 .

Cekić, Božidar Đ., Ivanovski, Valentin N., Codescu, Mirela, Umićević, Ana, Barudžija, Tanja, Patroi, Eros, "Mossbauer spectroscopic analysis of Nd2Fe14B/alpha-Fe hard magnetic nanocomposites" in Solid State Phenomena, 170 (2011):154-159,
https://doi.org/10.4028/www.scientific.net/SSP.170.154 . .

TY  - JOUR
AU  - Stojić, Dragica Lj.
AU  - Ćirić, Katarina D.
AU  - Cekić, Božidar Đ.
AU  - Koteski, Vasil J.
AU  - Zec, Slavica
AU  - Bogdanov, Žarko
PY  - 2011
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/4497
AB  - The hydrogenation properties of HfNi and Hf(2)Ni(7) intermetallics were investigated at the constant pressure of 1 bar and in the temperature ranges 373-573 K for HfNi and 323-473 K for Hf(2)Ni(7). The kinetic parameters, rate constants and activation energies of the absorption processes were determined. Maximal hydrogen absorption, i.e., number of hydrogen atoms absorbed per metal atom, HIM, are 1.05 and 0.04 achieved at 373 K for HfNi and Hf(2)Ni(7), respectively. Multiple hydriding/dehydriding was found to influence the improvement of the kinetic parameters. XRD and SEM methods were used to investigate the structural and morphological changes of the samples due to hydrogen absorption. The thermodynamic parameters of hydriding together with the structural properties of the intermetallics and their hydrides, calculated using the full-potential linearized augmented plane waves (FP-LAPW) code based on the density functional theory (DFT), were utilized for the sake of explaining the experimental investigations. Copyright (C) 2011, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.
T2  - International Journal of Hydrogen Energy
T1  - Hydrogenation properties of Hf-Ni intermetallics - Experimental and theoretical investigation
VL  - 36
IS  - 17
SP  - 10771
EP  - 10778
DO  - 10.1016/j.ijhydene.2011.05.131
ER  - 

@article{
author = "Stojić, Dragica Lj. and Ćirić, Katarina D. and Cekić, Božidar Đ. and Koteski, Vasil J. and Zec, Slavica and Bogdanov, Žarko",
year = "2011",
abstract = "The hydrogenation properties of HfNi and Hf(2)Ni(7) intermetallics were investigated at the constant pressure of 1 bar and in the temperature ranges 373-573 K for HfNi and 323-473 K for Hf(2)Ni(7). The kinetic parameters, rate constants and activation energies of the absorption processes were determined. Maximal hydrogen absorption, i.e., number of hydrogen atoms absorbed per metal atom, HIM, are 1.05 and 0.04 achieved at 373 K for HfNi and Hf(2)Ni(7), respectively. Multiple hydriding/dehydriding was found to influence the improvement of the kinetic parameters. XRD and SEM methods were used to investigate the structural and morphological changes of the samples due to hydrogen absorption. The thermodynamic parameters of hydriding together with the structural properties of the intermetallics and their hydrides, calculated using the full-potential linearized augmented plane waves (FP-LAPW) code based on the density functional theory (DFT), were utilized for the sake of explaining the experimental investigations. Copyright (C) 2011, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.",
journal = "International Journal of Hydrogen Energy",
title = "Hydrogenation properties of Hf-Ni intermetallics - Experimental and theoretical investigation",
volume = "36",
number = "17",
pages = "10771-10778",
doi = "10.1016/j.ijhydene.2011.05.131"
}

Stojić, D. Lj., Ćirić, K. D., Cekić, B. Đ., Koteski, V. J., Zec, S.,& Bogdanov, Ž.. (2011). Hydrogenation properties of Hf-Ni intermetallics - Experimental and theoretical investigation. in International Journal of Hydrogen Energy, 36(17), 10771-10778.
https://doi.org/10.1016/j.ijhydene.2011.05.131

Stojić DL, Ćirić KD, Cekić BĐ, Koteski VJ, Zec S, Bogdanov Ž. Hydrogenation properties of Hf-Ni intermetallics - Experimental and theoretical investigation. in International Journal of Hydrogen Energy. 2011;36(17):10771-10778.
doi:10.1016/j.ijhydene.2011.05.131 .

Stojić, Dragica Lj., Ćirić, Katarina D., Cekić, Božidar Đ., Koteski, Vasil J., Zec, Slavica, Bogdanov, Žarko, "Hydrogenation properties of Hf-Ni intermetallics - Experimental and theoretical investigation" in International Journal of Hydrogen Energy, 36, no. 17 (2011):10771-10778,
https://doi.org/10.1016/j.ijhydene.2011.05.131 . .

TY  - CONF
AU  - Cekić, Božidar Đ.
AU  - Umićević, Ana
AU  - Ivanovski, Valentin N.
AU  - Belošević-Čavor, Jelena
AU  - Koteski, Vasil J.
AU  - Hu, Rongwei
AU  - Petrović, Čedomir
PY  - 2010
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/6992
AB  - The perturbed angular correlation method has been employed to study the temperature dependence of the Ta-181 hyperfine interaction parameters in the poly-crystalline intermetallic compound alpha HfNi. At ambient temperature the frequency of the electric quadrupole interaction was omega(Q) = 26.0(2) Mrad/s and the asymmetry parameter eta = 0.22(1). The magnitude of the observed electric field gradient decreases with increasing temperature from 78 to 900 K. The calculations were done using the augmented plane wave plus local orbitals method as implemented in the WIEN2k code, using the generalized gradient approximation. In addition, a supercell calculation with Ta impurity located at the hafnium site was performed. The obtained result is in a good agreement with the experiment.
C3  - Hyperfine Interactions
T1  - Thermal evolution of the electric field gradient at Ta-181 in alpha HfNi
VL  - 196
IS  - 1-3
SP  - 339
EP  - 347
DO  - 10.1007/s10751-009-0135-1
ER  - 

@conference{
author = "Cekić, Božidar Đ. and Umićević, Ana and Ivanovski, Valentin N. and Belošević-Čavor, Jelena and Koteski, Vasil J. and Hu, Rongwei and Petrović, Čedomir",
year = "2010",
abstract = "The perturbed angular correlation method has been employed to study the temperature dependence of the Ta-181 hyperfine interaction parameters in the poly-crystalline intermetallic compound alpha HfNi. At ambient temperature the frequency of the electric quadrupole interaction was omega(Q) = 26.0(2) Mrad/s and the asymmetry parameter eta = 0.22(1). The magnitude of the observed electric field gradient decreases with increasing temperature from 78 to 900 K. The calculations were done using the augmented plane wave plus local orbitals method as implemented in the WIEN2k code, using the generalized gradient approximation. In addition, a supercell calculation with Ta impurity located at the hafnium site was performed. The obtained result is in a good agreement with the experiment.",
journal = "Hyperfine Interactions",
title = "Thermal evolution of the electric field gradient at Ta-181 in alpha HfNi",
volume = "196",
number = "1-3",
pages = "339-347",
doi = "10.1007/s10751-009-0135-1"
}

Cekić, B. Đ., Umićević, A., Ivanovski, V. N., Belošević-Čavor, J., Koteski, V. J., Hu, R.,& Petrović, Č.. (2010). Thermal evolution of the electric field gradient at Ta-181 in alpha HfNi. in Hyperfine Interactions, 196(1-3), 339-347.
https://doi.org/10.1007/s10751-009-0135-1

Cekić BĐ, Umićević A, Ivanovski VN, Belošević-Čavor J, Koteski VJ, Hu R, Petrović Č. Thermal evolution of the electric field gradient at Ta-181 in alpha HfNi. in Hyperfine Interactions. 2010;196(1-3):339-347.
doi:10.1007/s10751-009-0135-1 .

Cekić, Božidar Đ., Umićević, Ana, Ivanovski, Valentin N., Belošević-Čavor, Jelena, Koteski, Vasil J., Hu, Rongwei, Petrović, Čedomir, "Thermal evolution of the electric field gradient at Ta-181 in alpha HfNi" in Hyperfine Interactions, 196, no. 1-3 (2010):339-347,
https://doi.org/10.1007/s10751-009-0135-1 . .

TY  - JOUR
AU  - Dohcevic-Mitrovic, Z. D.
AU  - Paunović, Novica M.
AU  - Radović, Marko B.
AU  - Popović, Zoran V.
AU  - Matović, Branko
AU  - Cekić, Božidar Đ.
AU  - Ivanovski, Valentin N.
PY  - 2010
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/4007
AB  - Room-temperature ferromagnetism was observed in undoped and Fe(2+(3+))-doped CeO(2) nanocrystals. In Fe-doped samples the enhancement of ferromagnetic ordering occurs by changing the valence state of Fe ions, whereas Raman spectra demonstrated strong electron-molecular vibrational coupling and increase in oxygen vacancy concentration. Air annealing showed degradation of ferromagnetic ordering and appearance of hematite phase in Fe(3+)-doped sample. The observed ferromagnetic coupling in Fe-doped samples, associated with the presence of magnetic ions mediated by single charged O(2-) vacancies, demonstrated that valence state of dopant has a strong influence on magnetic properties of CeO(2) nanoparticles. (C) American Institute of Physics. [doi: 10.1063/1.3431581]
T2  - Applied Physics Letters
T1  - Valence state dependent room-temperature ferromagnetism in Fe-doped ceria nanocrystals
VL  - 96
IS  - 20
DO  - 10.1063/1.3431581
ER  - 

@article{
author = "Dohcevic-Mitrovic, Z. D. and Paunović, Novica M. and Radović, Marko B. and Popović, Zoran V. and Matović, Branko and Cekić, Božidar Đ. and Ivanovski, Valentin N.",
year = "2010",
abstract = "Room-temperature ferromagnetism was observed in undoped and Fe(2+(3+))-doped CeO(2) nanocrystals. In Fe-doped samples the enhancement of ferromagnetic ordering occurs by changing the valence state of Fe ions, whereas Raman spectra demonstrated strong electron-molecular vibrational coupling and increase in oxygen vacancy concentration. Air annealing showed degradation of ferromagnetic ordering and appearance of hematite phase in Fe(3+)-doped sample. The observed ferromagnetic coupling in Fe-doped samples, associated with the presence of magnetic ions mediated by single charged O(2-) vacancies, demonstrated that valence state of dopant has a strong influence on magnetic properties of CeO(2) nanoparticles. (C) American Institute of Physics. [doi: 10.1063/1.3431581]",
journal = "Applied Physics Letters",
title = "Valence state dependent room-temperature ferromagnetism in Fe-doped ceria nanocrystals",
volume = "96",
number = "20",
doi = "10.1063/1.3431581"
}

Dohcevic-Mitrovic, Z. D., Paunović, N. M., Radović, M. B., Popović, Z. V., Matović, B., Cekić, B. Đ.,& Ivanovski, V. N.. (2010). Valence state dependent room-temperature ferromagnetism in Fe-doped ceria nanocrystals. in Applied Physics Letters, 96(20).
https://doi.org/10.1063/1.3431581

Dohcevic-Mitrovic ZD, Paunović NM, Radović MB, Popović ZV, Matović B, Cekić BĐ, Ivanovski VN. Valence state dependent room-temperature ferromagnetism in Fe-doped ceria nanocrystals. in Applied Physics Letters. 2010;96(20).
doi:10.1063/1.3431581 .

Dohcevic-Mitrovic, Z. D., Paunović, Novica M., Radović, Marko B., Popović, Zoran V., Matović, Branko, Cekić, Božidar Đ., Ivanovski, Valentin N., "Valence state dependent room-temperature ferromagnetism in Fe-doped ceria nanocrystals" in Applied Physics Letters, 96, no. 20 (2010),
https://doi.org/10.1063/1.3431581 . .

TY  - JOUR
AU  - Cekić, Božidar Đ.
AU  - Umićević, Ana
AU  - Ivanovski, Valentin N.
AU  - Koteski, Vasil J.
AU  - Belošević-Čavor, Jelena
AU  - Pavlović, Suncan
PY  - 2009
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/6807
AB  - The time differential perturbed angular correlation technique was used to observe the magnetic dipole and electric quadrupole interactions of (181)Ta probe in the Ni-5 at.% Hf alloy from 78 to 1131 K. The presence of the Larmor precession frequency of (181)Ta in the Ni(Hf) solid solution phase confirms the Ni dominant concentration for the onset of ferromagnetism in the Ni-Hf alloys. A very weak quadrupole interaction originates from imperfections in the HfNi(5) phase formed during melting procedure. The third observed quadrupole interaction corresponds to the Ta probe in the HfO(2) contamination due to internal oxidation of the sample.
T2  - Journal of Alloys and Compounds
T1  - The time differential perturbed angular correlation study of the Ni-5 at.% Hf alloy
VL  - 480
IS  - 1
SP  - 40
EP  - 42
DO  - 10.1016/j.jallcom.2008.09.184
ER  - 

@article{
author = "Cekić, Božidar Đ. and Umićević, Ana and Ivanovski, Valentin N. and Koteski, Vasil J. and Belošević-Čavor, Jelena and Pavlović, Suncan",
year = "2009",
abstract = "The time differential perturbed angular correlation technique was used to observe the magnetic dipole and electric quadrupole interactions of (181)Ta probe in the Ni-5 at.% Hf alloy from 78 to 1131 K. The presence of the Larmor precession frequency of (181)Ta in the Ni(Hf) solid solution phase confirms the Ni dominant concentration for the onset of ferromagnetism in the Ni-Hf alloys. A very weak quadrupole interaction originates from imperfections in the HfNi(5) phase formed during melting procedure. The third observed quadrupole interaction corresponds to the Ta probe in the HfO(2) contamination due to internal oxidation of the sample.",
journal = "Journal of Alloys and Compounds",
title = "The time differential perturbed angular correlation study of the Ni-5 at.% Hf alloy",
volume = "480",
number = "1",
pages = "40-42",
doi = "10.1016/j.jallcom.2008.09.184"
}

Cekić, B. Đ., Umićević, A., Ivanovski, V. N., Koteski, V. J., Belošević-Čavor, J.,& Pavlović, S.. (2009). The time differential perturbed angular correlation study of the Ni-5 at.% Hf alloy. in Journal of Alloys and Compounds, 480(1), 40-42.
https://doi.org/10.1016/j.jallcom.2008.09.184

Cekić BĐ, Umićević A, Ivanovski VN, Koteski VJ, Belošević-Čavor J, Pavlović S. The time differential perturbed angular correlation study of the Ni-5 at.% Hf alloy. in Journal of Alloys and Compounds. 2009;480(1):40-42.
doi:10.1016/j.jallcom.2008.09.184 .

Cekić, Božidar Đ., Umićević, Ana, Ivanovski, Valentin N., Koteski, Vasil J., Belošević-Čavor, Jelena, Pavlović, Suncan, "The time differential perturbed angular correlation study of the Ni-5 at.% Hf alloy" in Journal of Alloys and Compounds, 480, no. 1 (2009):40-42,
https://doi.org/10.1016/j.jallcom.2008.09.184 . .

TY  - JOUR
AU  - Umićević, Ana
AU  - Cekić, Božidar Đ.
AU  - Ivanovski, Valentin N.
AU  - Koteski, Vasil J.
AU  - Belošević-Čavor, Jelena
AU  - Šiljegović, Milorad
AU  - Pavlović, S.
PY  - 2009
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/3694
AB  - The hyperfine interactions of Ta-181 probe in the nickel-2 at.% hafnium alloy have been studied by the perturbed angular correlation method in the temperature range 78-1131K. The magnitude of the magnetic dipole interaction of Hf-181/Ta-181 substituting in ferromagnetic Ni(Hf) solid solution decreases with increasing temperature. As a result of the restricted solid solubility of Hf in Ni, a second phase (HfNi5) in the Ni-Hf sample was detected. Hf-181/Ta-181 which resides in HfNi5 senses weak electric quadrupole interaction. The observed anomalous temperature behavior was ascribed to distortions in the HfNi5 cubic phase. The third measured hyperfine interaction corresponds to the quadrupole interaction of Hf-181/Ta-181 positioned in HfO2 contamination originating from an annealing procedure above 900 K.
T2  - Journal of Alloys and Compounds
T1  - Magnetic dipole and electric quadrupole interactions of 181Ta probe in Ni-Hf alloy
VL  - 475
IS  - 1-2
SP  - 38
EP  - 41
DO  - 10.1016/j.jallcom.2008.07.107
ER  - 

@article{
author = "Umićević, Ana and Cekić, Božidar Đ. and Ivanovski, Valentin N. and Koteski, Vasil J. and Belošević-Čavor, Jelena and Šiljegović, Milorad and Pavlović, S.",
year = "2009",
abstract = "The hyperfine interactions of Ta-181 probe in the nickel-2 at.% hafnium alloy have been studied by the perturbed angular correlation method in the temperature range 78-1131K. The magnitude of the magnetic dipole interaction of Hf-181/Ta-181 substituting in ferromagnetic Ni(Hf) solid solution decreases with increasing temperature. As a result of the restricted solid solubility of Hf in Ni, a second phase (HfNi5) in the Ni-Hf sample was detected. Hf-181/Ta-181 which resides in HfNi5 senses weak electric quadrupole interaction. The observed anomalous temperature behavior was ascribed to distortions in the HfNi5 cubic phase. The third measured hyperfine interaction corresponds to the quadrupole interaction of Hf-181/Ta-181 positioned in HfO2 contamination originating from an annealing procedure above 900 K.",
journal = "Journal of Alloys and Compounds",
title = "Magnetic dipole and electric quadrupole interactions of 181Ta probe in Ni-Hf alloy",
volume = "475",
number = "1-2",
pages = "38-41",
doi = "10.1016/j.jallcom.2008.07.107"
}

Umićević, A., Cekić, B. Đ., Ivanovski, V. N., Koteski, V. J., Belošević-Čavor, J., Šiljegović, M.,& Pavlović, S.. (2009). Magnetic dipole and electric quadrupole interactions of 181Ta probe in Ni-Hf alloy. in Journal of Alloys and Compounds, 475(1-2), 38-41.
https://doi.org/10.1016/j.jallcom.2008.07.107

Umićević A, Cekić BĐ, Ivanovski VN, Koteski VJ, Belošević-Čavor J, Šiljegović M, Pavlović S. Magnetic dipole and electric quadrupole interactions of 181Ta probe in Ni-Hf alloy. in Journal of Alloys and Compounds. 2009;475(1-2):38-41.
doi:10.1016/j.jallcom.2008.07.107 .

Umićević, Ana, Cekić, Božidar Đ., Ivanovski, Valentin N., Koteski, Vasil J., Belošević-Čavor, Jelena, Šiljegović, Milorad, Pavlović, S., "Magnetic dipole and electric quadrupole interactions of 181Ta probe in Ni-Hf alloy" in Journal of Alloys and Compounds, 475, no. 1-2 (2009):38-41,
https://doi.org/10.1016/j.jallcom.2008.07.107 . .

TY  - JOUR
AU  - Umićević, Ana
AU  - Belošević-Čavor, Jelena
AU  - Koteski, Vasil J.
AU  - Cekić, Božidar Đ.
AU  - Ivanovski, Valentin N.
PY  - 2009
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/6838
AB  - A detailed theoretical study of the structure and electric field gradients (EFG) of the Zr2Ni compound is presented. Using all-electron augmented plane waves plus local orbitals formalism, the equilibrium volume, bulk modulus, and EFGs at both non-equivalent crystallographic positions, Zr and Ni, are calculated. The possible mechanism of formation of the EFGs at both sites are analyzed and discussed. We have also performed supercell calculations with Cd and Ta impurities. Through the comparison of theoretical and experimental EFGs in these cases, we elucidate the role played by the Cd and Ta probe atoms in the time-differential perturbed angular correlation measurements of this compound.
T2  - International Journal of Materials Research
T1  - Electronic structure and electric field gradient calculations for the Zr2Ni intermetallic compound
VL  - 100
IS  - 9
SP  - 1239
EP  - 1241
DO  - 10.3139/146.110179
ER  - 

@article{
author = "Umićević, Ana and Belošević-Čavor, Jelena and Koteski, Vasil J. and Cekić, Božidar Đ. and Ivanovski, Valentin N.",
year = "2009",
abstract = "A detailed theoretical study of the structure and electric field gradients (EFG) of the Zr2Ni compound is presented. Using all-electron augmented plane waves plus local orbitals formalism, the equilibrium volume, bulk modulus, and EFGs at both non-equivalent crystallographic positions, Zr and Ni, are calculated. The possible mechanism of formation of the EFGs at both sites are analyzed and discussed. We have also performed supercell calculations with Cd and Ta impurities. Through the comparison of theoretical and experimental EFGs in these cases, we elucidate the role played by the Cd and Ta probe atoms in the time-differential perturbed angular correlation measurements of this compound.",
journal = "International Journal of Materials Research",
title = "Electronic structure and electric field gradient calculations for the Zr2Ni intermetallic compound",
volume = "100",
number = "9",
pages = "1239-1241",
doi = "10.3139/146.110179"
}

Umićević, A., Belošević-Čavor, J., Koteski, V. J., Cekić, B. Đ.,& Ivanovski, V. N.. (2009). Electronic structure and electric field gradient calculations for the Zr2Ni intermetallic compound. in International Journal of Materials Research, 100(9), 1239-1241.
https://doi.org/10.3139/146.110179

Umićević A, Belošević-Čavor J, Koteski VJ, Cekić BĐ, Ivanovski VN. Electronic structure and electric field gradient calculations for the Zr2Ni intermetallic compound. in International Journal of Materials Research. 2009;100(9):1239-1241.
doi:10.3139/146.110179 .

Umićević, Ana, Belošević-Čavor, Jelena, Koteski, Vasil J., Cekić, Božidar Đ., Ivanovski, Valentin N., "Electronic structure and electric field gradient calculations for the Zr2Ni intermetallic compound" in International Journal of Materials Research, 100, no. 9 (2009):1239-1241,
https://doi.org/10.3139/146.110179 . .

TY  - JOUR
AU  - Stojić, Dragica Lj.
AU  - Kumrić, Sandra V.
AU  - Belošević-Čavor, Jelena
AU  - Radaković, Jana
AU  - Cekić, Božidar Đ.
AU  - Mentus, Slavko V.
PY  - 2009
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/3719
AB  - The intermetallic compound (HfNi)-Ni-2 was the subject of investigations by several methods. The relative stability was checked by calculating its enthalpy and cohesive properties, using the augmented plane wave plus local orbitals (APW + lo) method of ab initio calculations. The kinetics of hydrogen absorption in this compound was investigated in the temperature range from 573 to 823 K, under the constant hydrogen pressure of 1 bar. The obtained rate constants, k (s(-1)), and hydriding capacities (H/M) are as follows: 0.00038 (0.69), 0.00131 (0.95), 0.00246 (1.13) and 0.0042 (0.92) for temperatures 573, 673, 723 and 823 K, respectively. The changes in crystal structure and morphology caused by multiple hydriding/dehydriding cycles were followed by XRD and SEM. (C) 2009 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.
T2  - International Journal of Hydrogen Energy
T1  - Hydridic, thermodynamic and kinetic properties of Hf2Ni intermetallic phase
VL  - 34
IS  - 9
SP  - 3764
EP  - 3770
DO  - 10.1016/j.ijhydene.2009.02.055
ER  - 

@article{
author = "Stojić, Dragica Lj. and Kumrić, Sandra V. and Belošević-Čavor, Jelena and Radaković, Jana and Cekić, Božidar Đ. and Mentus, Slavko V.",
year = "2009",
abstract = "The intermetallic compound (HfNi)-Ni-2 was the subject of investigations by several methods. The relative stability was checked by calculating its enthalpy and cohesive properties, using the augmented plane wave plus local orbitals (APW + lo) method of ab initio calculations. The kinetics of hydrogen absorption in this compound was investigated in the temperature range from 573 to 823 K, under the constant hydrogen pressure of 1 bar. The obtained rate constants, k (s(-1)), and hydriding capacities (H/M) are as follows: 0.00038 (0.69), 0.00131 (0.95), 0.00246 (1.13) and 0.0042 (0.92) for temperatures 573, 673, 723 and 823 K, respectively. The changes in crystal structure and morphology caused by multiple hydriding/dehydriding cycles were followed by XRD and SEM. (C) 2009 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.",
journal = "International Journal of Hydrogen Energy",
title = "Hydridic, thermodynamic and kinetic properties of Hf2Ni intermetallic phase",
volume = "34",
number = "9",
pages = "3764-3770",
doi = "10.1016/j.ijhydene.2009.02.055"
}

Stojić, D. Lj., Kumrić, S. V., Belošević-Čavor, J., Radaković, J., Cekić, B. Đ.,& Mentus, S. V.. (2009). Hydridic, thermodynamic and kinetic properties of Hf2Ni intermetallic phase. in International Journal of Hydrogen Energy, 34(9), 3764-3770.
https://doi.org/10.1016/j.ijhydene.2009.02.055

Stojić DL, Kumrić SV, Belošević-Čavor J, Radaković J, Cekić BĐ, Mentus SV. Hydridic, thermodynamic and kinetic properties of Hf2Ni intermetallic phase. in International Journal of Hydrogen Energy. 2009;34(9):3764-3770.
doi:10.1016/j.ijhydene.2009.02.055 .

Stojić, Dragica Lj., Kumrić, Sandra V., Belošević-Čavor, Jelena, Radaković, Jana, Cekić, Božidar Đ., Mentus, Slavko V., "Hydridic, thermodynamic and kinetic properties of Hf2Ni intermetallic phase" in International Journal of Hydrogen Energy, 34, no. 9 (2009):3764-3770,
https://doi.org/10.1016/j.ijhydene.2009.02.055 . .