57Fe Mössbauer study of CoCrxFe2-xO4 nano ferrite.

We report sol gel auto-combustion synthesized CoCr_xFe_2-xO₄ (x = 0.0 − 1.0) spinel ferrites, and use x-ray diffraction 'XRD', magnetic measurements, and Mössbauer spectroscopy to study the effect of Cr-content on their structural properties, magnetic properties, and correlation between them. Formation of single-phase nono spinel ferrite (grain size: 18.1 – 46.6 nm), is confirmed by XRD. Results show that with increasing Cr-content, lattice parameter decreases, and Cr³⁺ ions remain more populated on B-site, whereas Co²⁺ ions remains almost equally populated on both A, B site, show lower disorder, and modification of A–O − A, B– O − B, A–O − B super-exchange interaction. For Cr-content ≥ 0.75, Mössbauer measurements show presence of a non-magnetic doublet, and isomer shift values confirm that Fe has 3 + oxidation state. Observed structural changes, lead to reduction of saturation magnetization, coercivity. [ABSTRACT FROM AUTHOR]