Unveiling electronic structure and magnetic properties of AFe2O4 (A = Co, Ni, Zn, and Mg): Synergizing experimentation with DFT investigation

This study presents the synthesis of nano-crystalline spinel ferrites AFe2O4 (A = Co2+, Ni+2, Zn+2, and Mg+2), through the sol-gel method, yielding crystallite sizes ranging from 12 to 28 nm. The variation in IR and Raman spectra due to M-O-M bonding supports the variation in lattice parameters. The magnetization measurements revealed that CoFe2O4 has a high saturation magnetization of ∼55 emu/g and coercivity of ∼1350 Oe, while ZnFe2O4 exhibited saturation magnetization value of ∼8 emu/g and coercivity of ∼16 Oe. In addition, the electronic structure calculated using DFT, which corroborated the antiparallel alignment of Fe ions in the tetrahedral and octahedral sites, validating the measured magnetic moments. Notably, the CoFe2O4 ferrite exhibited a higher squareness ratio than other ferrites, signifying its suitability as a magnetic material for audio-video recording.