Influence of oxygen vacancies on the structure and magnetic properties of high entropy (Co,Cr,Fe,Mn,Ni)3O4 ceramics

摘要

This research revealed the influence of oxygen vacancies on the structure and magnetic properties of high entropy (Co,Cr,Fe,Mn,Ni)(3)O-4 ceramics. High entropy (Co,Cr,Fe,Mn,Ni)(3)O-4 and (Co,Cr,Fe,Mn,Ni)(3)O4-n ceramics with a single-phase spinel structure was synthesized by surfactant-assisted hydrothermal technology combined with a heat treatment method. X-ray diffraction Rietveld analysis showed that the lattice constant of (Co,Cr,Fe,Mn,Ni)(3)O-4 and (Co,Cr,Fe,Mn,Ni)(3)O4-n were 8.346 A and 8.327 angstrom, whereas the lattice distortion were 0.314-0.007, respectively. Magnetic studies indicate that all synthesized samples exhibit typical ferrimagnetism at 5-300 K. Compared with (Co,Cr,Fe,Mn,Ni)(3)O-4, the Hc of (Co,Cr,Fe,Mn,Ni)(3)O4-n increased from 7.99 center dot 10 Oe to 9.03 center dot 10 Oe, the Ms increased from 4.38 emu center dot g(-1) to 6.59 emu center dot g(-1) at room temperature. The theory calculations reveal that the 3d TM atoms are origin of the magnetism. And compared with (Co,Cr,Fe,Mn,Ni)(3)O-4, the spin density of metal atoms of (Co,Cr,Fe,Mn,Ni)(3)O4-n increases and the direction change. Our observation and theoretical calculations serve as a link between the defect, structure, and magnetic properties, providing a new sight into understanding the structural origin of the changes in magnetic properties of high entropy ceramics.

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