Exchange bias in phase-segregated Nd2/3Ca1/3MnO3 as a function of temperature and cooling magnetic fields

TL;DR

This study investigates exchange bias phenomena in Nd2/3Ca1/3MnO3, revealing how temperature and cooling magnetic fields influence magnetic properties and phase segregation, with implications for magnetic material applications.

Contribution

It provides new insights into the dependence of exchange bias and coercivity on temperature and cooling fields in Nd2/3Ca1/3MnO3, highlighting phase evolution effects.

Findings

Exchange bias appears below 70 K and depends on cooling field strength.

Exchange bias diminishes as temperature approaches Curie point.

Training effects indicate non-equilibrium magnetic state relaxation.

Abstract

Exchange bias (EB) phenomena have been observed in Nd2/3Ca1/3MnO3 colossal magnetoresistance perovskite below the Curie temperature $T_{C}$ = 70 K and attributed to an antiferromagnetic (AFM) - ferromagnetic (FM) spontaneous phase segregated state of this compound. Field cooled magnetic hysteresis loops exhibit shifts toward negative direction of the magnetic field axis. The values of exchange field $H_{EB}$ and coercivity $H_{C}$ are found to be strongly dependent of temperature and strength of the cooling magnetic field $H_{cool}$. These effects are attributed to evolution of the FM phase content and a size of FM clusters. A contribution to the total magnetization of the system due to the FM phase has been evaluated. The exchange bias effect decreases with increasing temperature up to $T_{C}$ and vanishes above this temperature with disappearance of FM phase. Relaxation of a non-equilibrium magnetic state of the compound manifests itself through a training effect also observed while studying EB in Nd2/3Ca1/3MnO3.