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  - Lazarević, Zorica Ž.
AU  - Milutinovic, Aleksandra N.
AU  - Jovalekić, Čedomir
AU  - Ivanovski, Valentin N.
AU  - Daneu, Nina
AU  - Mađarević, Ivan
AU  - Romčević, Nebojša Ž.
PY  - 2015
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/386
AB  - Nano crystalline samples of nickel zinc ferrite, Ni0.5Zn0.5Fe2O4 were prepared by mechanochemical route in a planetary ball mill starting from two mixtures of the appropriate quantities of the powders: case (1) oxide powders: NiO, ZnO and alpha-Fe2O3 in one case, and in the second case (2) hydroxide powders: Ni(OH)(2), Zn(OH)(2) and Fe(OH)(3). In order to monitor the progress of chemical reaction and confirm phase formation, powder samples obtained after 5 h and 10 h of milling were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), Raman, IR and Mossbauer spectroscopy. It is shown that the soft mechanochemical method, i.e. mechanochemical activation of hydroxides, produces high quality single phase Ni0.5Zn0.5Fe2O4 samples in much more efficient way. From the IR spectroscopy of single phase samples it is obvious that energy of modes depends on the ratio of cations. The deconvolution of Raman spectra allows to separate contributions of different cations to a particular type of vibration and to estimate the degree of inversion. (C) 2014 Elsevier Ltd. All rights reserved.
T2  - Materials Research Bulletin
T1  - Spectroscopy investigation of nanostructured nickel-zinc ferrite obtained by mechanochemical synthesis
VL  - 63
SP  - 239
EP  - 247
DO  - 10.1016/j.materresbull.2014.12.005
ER  - 

@article{
author = "Lazarević, Zorica Ž. and Milutinovic, Aleksandra N. and Jovalekić, Čedomir and Ivanovski, Valentin N. and Daneu, Nina and Mađarević, Ivan and Romčević, Nebojša Ž.",
year = "2015",
abstract = "Nano crystalline samples of nickel zinc ferrite, Ni0.5Zn0.5Fe2O4 were prepared by mechanochemical route in a planetary ball mill starting from two mixtures of the appropriate quantities of the powders: case (1) oxide powders: NiO, ZnO and alpha-Fe2O3 in one case, and in the second case (2) hydroxide powders: Ni(OH)(2), Zn(OH)(2) and Fe(OH)(3). In order to monitor the progress of chemical reaction and confirm phase formation, powder samples obtained after 5 h and 10 h of milling were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), Raman, IR and Mossbauer spectroscopy. It is shown that the soft mechanochemical method, i.e. mechanochemical activation of hydroxides, produces high quality single phase Ni0.5Zn0.5Fe2O4 samples in much more efficient way. From the IR spectroscopy of single phase samples it is obvious that energy of modes depends on the ratio of cations. The deconvolution of Raman spectra allows to separate contributions of different cations to a particular type of vibration and to estimate the degree of inversion. (C) 2014 Elsevier Ltd. All rights reserved.",
journal = "Materials Research Bulletin",
title = "Spectroscopy investigation of nanostructured nickel-zinc ferrite obtained by mechanochemical synthesis",
volume = "63",
pages = "239-247",
doi = "10.1016/j.materresbull.2014.12.005"
}

Lazarević, Z. Ž., Milutinovic, A. N., Jovalekić, Č., Ivanovski, V. N., Daneu, N., Mađarević, I.,& Romčević, N. Ž.. (2015). Spectroscopy investigation of nanostructured nickel-zinc ferrite obtained by mechanochemical synthesis. in Materials Research Bulletin, 63, 239-247.
https://doi.org/10.1016/j.materresbull.2014.12.005

Lazarević ZŽ, Milutinovic AN, Jovalekić Č, Ivanovski VN, Daneu N, Mađarević I, Romčević NŽ. Spectroscopy investigation of nanostructured nickel-zinc ferrite obtained by mechanochemical synthesis. in Materials Research Bulletin. 2015;63:239-247.
doi:10.1016/j.materresbull.2014.12.005 .

Lazarević, Zorica Ž., Milutinovic, Aleksandra N., Jovalekić, Čedomir, Ivanovski, Valentin N., Daneu, Nina, Mađarević, Ivan, Romčević, Nebojša Ž., "Spectroscopy investigation of nanostructured nickel-zinc ferrite obtained by mechanochemical synthesis" in Materials Research Bulletin, 63 (2015):239-247,
https://doi.org/10.1016/j.materresbull.2014.12.005 . .

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  - Radaković, Jana
AU  - Batalović, Katarina
AU  - Mađarević, Ivan
AU  - Belošević-Čavor, Jelena
PY  - 2014
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/194
AB  - Understanding the microscopic aspect of the hydride formation process provides an insight into the experimentally observed properties of prospective hydrogen storage materials. In this paper, we have studied the local structural and electronic modifications induced by hydrogen absorption in cubic C15 Laves phases AB(2) (A = Zr; B = Cr, Mn, Ni), as well as the stability of the formed hydrides, by means of density functional theory (DFT). To address the effect of hydrogen absorbed in one of three tetrahedral sites (96g, 32e, and 8b) on the electronic structure of its surrounding atoms, we have calculated the electric field gradient (EFG) on the position of Cr, Mn, and Ni in pure and hydrogenated compounds. EFG is associated with the hydrogen site-preference, and formation enthalpies of ZrB2H hydrides are used to examine their formation feasibility. Obtained enthalpies reveal that ZrMn2H and ZrNi2H are both unstable regardless of the occupied site, and the only attainable hydride is ZrCr2H, with comparable occupational probability of sites 96g and 32e. EFG results indicate that a hydrogen distribution within the crystal depends on the level of induced electronic structure modifications; i.e., the hydrogen site-preference is governed by the condition of minimal divergence of the electronic charge from its initial distribution.
T2  - RSC Advances
T1  - Interstitial hydrogen in Laves phases - local electronic structure modifications from first-principles
VL  - 4
IS  - 97
SP  - 54769
EP  - 54774
DO  - 10.1039/c4ra09082a
ER  - 

@article{
author = "Radaković, Jana and Batalović, Katarina and Mađarević, Ivan and Belošević-Čavor, Jelena",
year = "2014",
abstract = "Understanding the microscopic aspect of the hydride formation process provides an insight into the experimentally observed properties of prospective hydrogen storage materials. In this paper, we have studied the local structural and electronic modifications induced by hydrogen absorption in cubic C15 Laves phases AB(2) (A = Zr; B = Cr, Mn, Ni), as well as the stability of the formed hydrides, by means of density functional theory (DFT). To address the effect of hydrogen absorbed in one of three tetrahedral sites (96g, 32e, and 8b) on the electronic structure of its surrounding atoms, we have calculated the electric field gradient (EFG) on the position of Cr, Mn, and Ni in pure and hydrogenated compounds. EFG is associated with the hydrogen site-preference, and formation enthalpies of ZrB2H hydrides are used to examine their formation feasibility. Obtained enthalpies reveal that ZrMn2H and ZrNi2H are both unstable regardless of the occupied site, and the only attainable hydride is ZrCr2H, with comparable occupational probability of sites 96g and 32e. EFG results indicate that a hydrogen distribution within the crystal depends on the level of induced electronic structure modifications; i.e., the hydrogen site-preference is governed by the condition of minimal divergence of the electronic charge from its initial distribution.",
journal = "RSC Advances",
title = "Interstitial hydrogen in Laves phases - local electronic structure modifications from first-principles",
volume = "4",
number = "97",
pages = "54769-54774",
doi = "10.1039/c4ra09082a"
}

Radaković, J., Batalović, K., Mađarević, I.,& Belošević-Čavor, J.. (2014). Interstitial hydrogen in Laves phases - local electronic structure modifications from first-principles. in RSC Advances, 4(97), 54769-54774.
https://doi.org/10.1039/c4ra09082a

Radaković J, Batalović K, Mađarević I, Belošević-Čavor J. Interstitial hydrogen in Laves phases - local electronic structure modifications from first-principles. in RSC Advances. 2014;4(97):54769-54774.
doi:10.1039/c4ra09082a .

Radaković, Jana, Batalović, Katarina, Mađarević, Ivan, Belošević-Čavor, Jelena, "Interstitial hydrogen in Laves phases - local electronic structure modifications from first-principles" in RSC Advances, 4, no. 97 (2014):54769-54774,
https://doi.org/10.1039/c4ra09082a . .