Weak ferromagnetism and exchange bias effect in Co1+yAl2-yO4/SiO2 nanocomposites
Abstract
Nanocomposites made of magnetic spinel oxide Co1+yAl2-yO4 nanoparticles (NPs) with y = 0.93, 1.20 and 1.34 dispersed in an amorphous SiO2 matrix were prepared by a sol-gel method. The average crystallite size DXRD of about 25 nm determined by X-ray diffraction (XRD) agrees well with the average particle size observed in transmission electron microscopy (TEM). Dynamic magnetic susceptibility measurements indicate a spin-glass-like behavior of the nanoparticles below the spin-glass (SG) transition temperature TC < 10 K. Field dependent magnetization exhibits weak ferromagnetism and shift of the magnetic hysteresis loop. On the basis of the observed magnetic properties, we propose a model of the core-shell structure of the Co1+yAl2-yO4 nanoparticles with the spin-glass phase in the core and weak ferromagnetism in the shell. The exchange bias field disappears above the spin-glass transition temperature TC, whereas the weak ferromagnetism persists also at temperatures above TC. The componen...t of weak ferromagnetism is associated with the presence of Co vacancies in the nanoparticle spinel crystal lattice.
Keywords:
Cobalt aluminum oxide / Cobalt vacancies / Magnetic exchange coupling / Nanoparticles / Spin-glass / Weak ferromagnetismSource:
Journal of Alloys and Compounds, 2021, 853, 155933-Funding / projects:
- Ministry of Education, Science and Technological Development of the Republic of Serbia
DOI: 10.1016/j.jallcom.2020.155933
ISSN: 0925-8388
WoS: 000582806400002
Scopus: 2-s2.0-85091572546
Institution/Community
VinčaTY - JOUR AU - Babić-Stojić, Branka S. AU - Branković, Dušan AU - Milivojević, Dušan AU - Jagličić, Zvonko PY - 2021 UR - https://vinar.vin.bg.ac.rs/handle/123456789/9646 AB - Nanocomposites made of magnetic spinel oxide Co1+yAl2-yO4 nanoparticles (NPs) with y = 0.93, 1.20 and 1.34 dispersed in an amorphous SiO2 matrix were prepared by a sol-gel method. The average crystallite size DXRD of about 25 nm determined by X-ray diffraction (XRD) agrees well with the average particle size observed in transmission electron microscopy (TEM). Dynamic magnetic susceptibility measurements indicate a spin-glass-like behavior of the nanoparticles below the spin-glass (SG) transition temperature TC < 10 K. Field dependent magnetization exhibits weak ferromagnetism and shift of the magnetic hysteresis loop. On the basis of the observed magnetic properties, we propose a model of the core-shell structure of the Co1+yAl2-yO4 nanoparticles with the spin-glass phase in the core and weak ferromagnetism in the shell. The exchange bias field disappears above the spin-glass transition temperature TC, whereas the weak ferromagnetism persists also at temperatures above TC. The component of weak ferromagnetism is associated with the presence of Co vacancies in the nanoparticle spinel crystal lattice. T2 - Journal of Alloys and Compounds T1 - Weak ferromagnetism and exchange bias effect in Co1+yAl2-yO4/SiO2 nanocomposites VL - 853 SP - 155933 DO - 10.1016/j.jallcom.2020.155933 ER -
@article{ author = "Babić-Stojić, Branka S. and Branković, Dušan and Milivojević, Dušan and Jagličić, Zvonko", year = "2021", abstract = "Nanocomposites made of magnetic spinel oxide Co1+yAl2-yO4 nanoparticles (NPs) with y = 0.93, 1.20 and 1.34 dispersed in an amorphous SiO2 matrix were prepared by a sol-gel method. The average crystallite size DXRD of about 25 nm determined by X-ray diffraction (XRD) agrees well with the average particle size observed in transmission electron microscopy (TEM). Dynamic magnetic susceptibility measurements indicate a spin-glass-like behavior of the nanoparticles below the spin-glass (SG) transition temperature TC < 10 K. Field dependent magnetization exhibits weak ferromagnetism and shift of the magnetic hysteresis loop. On the basis of the observed magnetic properties, we propose a model of the core-shell structure of the Co1+yAl2-yO4 nanoparticles with the spin-glass phase in the core and weak ferromagnetism in the shell. The exchange bias field disappears above the spin-glass transition temperature TC, whereas the weak ferromagnetism persists also at temperatures above TC. The component of weak ferromagnetism is associated with the presence of Co vacancies in the nanoparticle spinel crystal lattice.", journal = "Journal of Alloys and Compounds", title = "Weak ferromagnetism and exchange bias effect in Co1+yAl2-yO4/SiO2 nanocomposites", volume = "853", pages = "155933", doi = "10.1016/j.jallcom.2020.155933" }
Babić-Stojić, B. S., Branković, D., Milivojević, D.,& Jagličić, Z.. (2021). Weak ferromagnetism and exchange bias effect in Co1+yAl2-yO4/SiO2 nanocomposites. in Journal of Alloys and Compounds, 853, 155933. https://doi.org/10.1016/j.jallcom.2020.155933
Babić-Stojić BS, Branković D, Milivojević D, Jagličić Z. Weak ferromagnetism and exchange bias effect in Co1+yAl2-yO4/SiO2 nanocomposites. in Journal of Alloys and Compounds. 2021;853:155933. doi:10.1016/j.jallcom.2020.155933 .
Babić-Stojić, Branka S., Branković, Dušan, Milivojević, Dušan, Jagličić, Zvonko, "Weak ferromagnetism and exchange bias effect in Co1+yAl2-yO4/SiO2 nanocomposites" in Journal of Alloys and Compounds, 853 (2021):155933, https://doi.org/10.1016/j.jallcom.2020.155933 . .