Structural, electronic and magnetic properties of Fe doped CoCr$_{2}$O$_{4}$: insights from ab initio calculations

TL;DR

This study uses ab initio calculations to analyze how Fe doping alters the structural, electronic, and magnetic properties of CoCr2O4, revealing tendencies towards inverse spinel formation and implications for magnetic behavior.

Contribution

It provides a detailed microscopic understanding of Fe substitution effects on CoCr2O4's properties, including magnetic interactions and structural tendencies, based on first-principles calculations.

Findings

Fe doping influences magnetic moments and exchange interactions.

Increasing Fe concentration promotes inverse spinel structure formation.

Alterations in magnetic exchange interactions affect multiferroic properties.

Abstract

CoCr$_2$O$_4$ has attracted significant attention recently due to several interesting properties such as magnetostriction, magnetoelectricity etc.. More recent experiments on Fe substituted CoCr$_2$O$_4$ observed a variety of novel phenomena such as the magnetic compensation accompanied by the occurrence of exchange bias, which reverses its sign. Understanding of such phenomena may lead to control the properties of these material in an efficient way to enhance its potential for multifunctional applications. In this paper, we study the microscopic understanding of Fe doping in modifying the structural and magnetic properties of CoCr$_{2}$O$_{4}$ with varying composition and substitution of Fe at different sublattices by first-principles density functional calculations. We have analysed in detail the effect of Fe substitution on crystal field and exchange splittings, magnetic moments and interatomic exchange parameters. It is also observed that with increasing concentration of Fe impurity, the system has a tendency towards forming an "Inverse Spinel" structure as observed in experiments. Such tendencies are crucial to understand this system as it would lead to modifications in the magnetic exchange interactions associated with sites with different symmetry finally affecting the magnetic structure and the multiferrocity in turn.