Exchange bias and memory effect in Sr$_2$FeCoO$_6$

TL;DR

This paper investigates exchange bias and memory effects in Sr$_2$FeCoO$_6$, revealing the role of antiphase boundaries and spin glass behavior, with detailed magnetic characterization and analysis of the glassy phase dynamics.

Contribution

It demonstrates the presence of exchange bias and memory effects in Sr$_2$FeCoO$_6$, linking them to antiphase boundaries and spin glass phenomena, which is a novel insight for this material.

Findings

Exchange bias depends on cooling field and temperature.

Spin glass transition follows Almeida-Thouless line.

Magnetic relaxation reveals glassy phase dynamics.

Abstract

We report on the observation of exchange bias and memory effect in double perovskite Sr$_2$FeCoO$_6$. Antiphase boundaries between the ferromagnetic and antiferromagnetic regions in the disordered glassy phase is assumed as responsible for the observed effect which reflects in the cooling field dependence and temperature evolution of exchange bias field and in training effect. The spin glass phase itself is characterized through memory, ageing and magnetic relaxation experiments. The spin glass transition temperature, $T_g$, versus $H_{dc}^{2/3}$ follows the Almeida-Thouless line yielding a freezing temperature, $T_f$ = 73 K. Time-dependent magnetic relaxation studies reveal the magnetization dynamics of the underlying glassy phase in this double perovskite.