Antisite Disorder-induced Exchange Bias Effect in Multiferroic Y2CoMnO6

TL;DR

This study reports the observation of exchange bias in the multiferroic Y2CoMnO6, caused by antisite disorder creating ferromagnetic and antiferromagnetic interfaces, with detailed analysis of magnetic properties below 8 K.

Contribution

It demonstrates how antisite disorder induces exchange bias in a multiferroic double perovskite, providing a model for the domain growth mechanism involved.

Findings

Exchange bias observed below 8 K.

Significant coercive field of approximately 10 kOe.

Ferromagnetic hysteresis with metamagnetic steps.

Abstract

Exchange bias effect in the ferromagnetic double perovskite compound Y$_2$CoMnO$_6$, which is also a multiferroic, is reported. The exchange bias, observed below 8~K, is explained as arising due to the interface effect between the ferromagnetic and antiferromagnetic clusters created by {\it antisite} disorder in this material. Below 8~K, prominent ferromagnetic hysteresis with metamagnetic "steps" and significant coercive field, $H_c \approx$ 10~kOe are observed in this compound which has a $T_c \approx$ 75~K. A model based on growth of ferromagnetic domains overcoming the elastic energy of structurally pinned magnetic interfaces, which closely resembles martensitic-like transitions, is adapted to explain the observed effects. The role of {\it antisite} disorder in creating the domain structure leading to exchange bias effect is highlighted in the present work.