Correlation of exchange bias with magneto-structural effects across the compensation temperature of Co(Cr$_{1-x}$Fe$_{x}$)$_2$O$_4$ (x = 0.05 and 0.075)

TL;DR

This study investigates how small Fe substitutions in CoCr2O4 influence exchange bias and magneto-structural effects, revealing a sign change in exchange bias linked to lattice and disorder changes across the compensation temperature.

Contribution

It demonstrates the correlation between exchange bias sign change and magneto-structural effects in Fe-substituted CoCr2O4, highlighting the role of lattice and disorder energies.

Findings

Sign change in exchange bias across compensation temperature

Non-monotonic variation of local magnetic moments

Correlation between lattice structure and magnetic properties

Abstract

A small amount of Fe (5% and 7.5%) substitution in the Cr-site of the multiferroic compound CoCr2O4 leads to a magnetization reversal. In these compounds, we report a sign change in the exchange bias across the compensation temperature, accompanied by a non-monotonic change in the local moments across the compensation temperature. Such non-monotonic change in the magnetic moments is triggered by a similar change in the lattice structure. We relate here the sign change of exchange bias with that of the crystalline energy of the lattice and the Zeeman energy term arising from the anti-site disorder.