Exchange bias-like effect in TbFeAl intermetallic induced by atomic disorder

TL;DR

This study reports an exchange bias-like effect in the intermetallic compound TbFeAl caused by atomic disorder, revealing new multifunctional magnetic properties and expanding understanding of exchange bias in disordered materials.

Contribution

It demonstrates the occurrence of exchange bias in TbFeAl due to atomic disorder, a novel finding linking crystallographic disorder with magnetic exchange bias effects.

Findings

Exchange bias-like effect observed below 10 K.

Significant coercive field of about 1.5 T at 2 K.

Exchange bias field levels off with increasing temperature.

Abstract

Exchange bias-like effect observed in the intermetallic compound TbFeAl, which displays a magnetic phase transition at $T^h_c \approx$ 198~K and a second one at $T^l_c \approx$ 154~K, is reported. {\em Jump}-like features are observed in the isothermal magnetization, $M (H)$, at 2~K which disappear above 8~K. The field-cooled magnetization isotherms below 10~K show loop-shifts that are reminiscent of exchange bias, also supported by {\em training effect}. Significant coercive field, $H_c \approx$ 1.5~T at 2~K is observed in TbFeAl which, after an initial increase, shows subsequent decrease with temperature. The exchange bias field, $H_{eb}$, shows a slight increase and subsequent leveling off with temperature. It is argued that the inherent crystallographic disorder among Fe and Al and the high magnetocrystalline anisotropy related to Tb$^{3+}$ lead to the exchange bias effect. TbFeAl is recently reported to show magnetocaloric effect and the present discovery of exchange bias makes this compound a multifunctional one. The result obtained on TbFeAl generalizes the observation of exchange bias in crystallographically disordered materials and gives impetus for the search for materials with {\em exchange bias induced by atomic disorder.}