Large zero-field cooled exchange-bias in bulk Mn2PtGa

TL;DR

This study demonstrates a significant zero-field cooled exchange-bias effect in bulk Mn2PtGa, driven by ferrimagnetic ordering and complex magnetic phases, revealing new magnetic phenomena in this Heusler compound.

Contribution

It uncovers the large zero-field cooled exchange-bias in Mn2PtGa and links it to ferrimagnetic order and intrinsic disorder, providing new insights into magnetic behavior in Heusler alloys.

Findings

Large exchange-bias observed after zero-field cooling.

Ferrimagnetic order is crucial for inducing exchange anisotropy.

Presence of spin-glass-like phase and field-induced irreversibility.

Abstract

We report a large exchange-bias (EB) effect after zero-field cooling the new tetragonal Heusler compound Mn2PtGa from the paramagnetic state. The first-principle calculation and the magnetic measurements reveal that Mn2PtGa orders ferrimagnetically with some ferromagnetic (FM) inclusions. We show that ferrimagnetic (FI) ordering is essential to isothermally induce the exchange anisotropy needed for the zero-field cooled (ZFC) EB during the virgin magnetization process. The complex magnetic behavior at low temperatures is characterized by the coexistence of a field induced irreversible magnetic behavior and a spin-glass-like phase. The field induced irreversibility originates from an unusual first-order FI to antiferromagnetic transition, whereas, the spin-glass like state forms due to the existence of anti-site disorder intrinsic to the material.