Intrinsic interface exchange coupling of ferromagnetic nanodomains in a charge ordered manganite

TL;DR

This study reveals intrinsic interface exchange coupling in phase-separated manganites, showing small ferromagnetic nanodomains within a charge-ordered antiferromagnetic matrix, with exchange bias effects and a training effect explained by a relaxation model.

Contribution

First evidence of intrinsic interface exchange coupling in phase-separated manganites, linking nanodomains to exchange bias phenomena.

Findings

Presence of ferromagnetic nanodomains within charge-ordered AFM host.

Observation of exchange bias under field cooling.

Training effect consistent with a relaxation model.

Abstract

We present a detailed magnetic study of the Pr1/3Ca2/3MnO3 manganite, where we observe the presence of small ferromagnetic (FM) domains (diameter ~ 10A) immersed within the charge-ordered antiferromagnetic (AFM) host. Due to the interaction of the FM nanodroplets with a disordered AFM shell, the low-temperature magnetization loops present exchange bias (EB) under cooling in an applied magnetic field. Our analysis of the cooling field dependence of the EB yields an antiferromagnetic interface exchange coupling comparable to the bulk exchange constant of the AFM phase. We also observe training effect of the EB, which is successfully described in terms of a preexisting relaxation model developed for other classical EB systems. This work provides the first evidence of intrinsic interface exchange coupling in phase separated manganites.