Tunable giant exchange bias in single-phase rare earth-transition metal intermetallics YMn12-xFex with highly homogenous inter-sublattice exchange coupling

TL;DR

This study reports a family of intermetallic compounds exhibiting tunable giant exchange bias due to homogeneous inter-sublattice interactions, with potential implications for magnetic device applications.

Contribution

We discovered a new class of YMn12-xFex intermetallics showing bulk tunable giant exchange bias driven by homogeneous inter-sublattice exchange interactions, not interfacial effects.

Findings

Giant exchange bias up to 6.1 kOe observed in YMn4.4Fe7.6

Exchange bias can be switched off with temperature

Homogeneous inter-sublattice exchange coupling confirmed by theory

Abstract

In this paper, we have found a family of intermetallic compounds YMn12-xFex (x = 6.6-8.8) showing a bulk form of tunable giant exchange bias effect which arises from global interactions among ferromagnetic (FM) and antiferromagnetic (AFM) sublattices but not the interfacial exchange coupling or inhomogeneous magnetic clusters. A giant exchange bias with a loop shift up to 6.1 kOe has been observed in YMn4.4Fe7.6 compound with the strongest competing magnetic interactions. In a narrow temperature range, the exchange bias field shows a sudden switching off whereas the coercivity shows a sudden switching on with increasing temperature. This unique feature indicates that the inter-sublattice exchange coupling is highly homogenous, which can be perfectly interperated by our theoretical calculations.