TY - JOUR
T1 - Structural and magnetic properties of vacuum and air annealed CoFe2O4 nanoparticles
AU - Ragunath, Balaji Srikanth
AU - Thileeba, A.
AU - Meher, K. R.S.Preethi
AU - Chinnathambi, Karthik
AU - Sathya, Ayyappan
N1 - Publisher Copyright:
© 2025 Elsevier Ltd
PY - 2025/10/1
Y1 - 2025/10/1
N2 - CoFe2O4 (CFO) nanoparticles (NPs) were synthesized by co-precipitation technique and annealed up to 1273K under air and vacuum atmospheres. X-ray diffraction (XRD) analysis of pristine, vacuum and air - annealed samples confirms the spinel structure without any secondary phases. Transmission electron microscopy (TEM) of pristine CFO NPs confirms a wider distribution with an average particle size of 26 ± 7 nm. Further, the estimated activation energy for the growth of CFO NPs under vacuum and air atmosphere is 14.5 kJ/mol and 20.4 kJ/mol respectively. A relative decrease in activation energy for the vacuum − annealed samples suggest part of the thermal energy is utilized for cation migration between the interstitial sites of the spinel structure. Further, the cation migration is unambiguously confirmed by Raman spectroscopy. This study further reveals that the improved saturation magnetization upon vacuum annealing (from 47 emu/g to 80 emu/g) compared to air annealing (76 emu/g) is mainly due to the cation migration and the creation of oxygen vacancies.
AB - CoFe2O4 (CFO) nanoparticles (NPs) were synthesized by co-precipitation technique and annealed up to 1273K under air and vacuum atmospheres. X-ray diffraction (XRD) analysis of pristine, vacuum and air - annealed samples confirms the spinel structure without any secondary phases. Transmission electron microscopy (TEM) of pristine CFO NPs confirms a wider distribution with an average particle size of 26 ± 7 nm. Further, the estimated activation energy for the growth of CFO NPs under vacuum and air atmosphere is 14.5 kJ/mol and 20.4 kJ/mol respectively. A relative decrease in activation energy for the vacuum − annealed samples suggest part of the thermal energy is utilized for cation migration between the interstitial sites of the spinel structure. Further, the cation migration is unambiguously confirmed by Raman spectroscopy. This study further reveals that the improved saturation magnetization upon vacuum annealing (from 47 emu/g to 80 emu/g) compared to air annealing (76 emu/g) is mainly due to the cation migration and the creation of oxygen vacancies.
KW - Activation energy
KW - Cation migration
KW - Cobalt ferrite
KW - Magnetism
KW - Oxygen vacancy
KW - Spinel structure
KW - Vacuum annealing
UR - https://www.scopus.com/pages/publications/105013125921
U2 - 10.1016/j.ssc.2025.116107
DO - 10.1016/j.ssc.2025.116107
M3 - Article
AN - SCOPUS:105013125921
SN - 0038-1098
VL - 404
JO - Solid State Communications
JF - Solid State Communications
M1 - 116107
ER -