Field-induced multiple metamagnetization in phase transition from paramagnetic austenite to ferromagnetic martensite in MnNi1-xFexGe

TL;DR

This study demonstrates a magnetic-field-induced martensitic transformation in MnNi1-xFexGe, where doping with Fe aligns structural and magnetic transitions at room temperature, leading to significant magnetization changes.

Contribution

It introduces a method to induce and control multiple metamagnetization processes via field-induced phase transitions in MnNi1-xFexGe alloys.

Findings

Large magnetization difference of up to 50 emu/g across transformation

Field-induced multiple metamagnetization process observed

Structural and magnetic transitions coincide at room temperature

Abstract

Tailoring the phase stability and magnetic structure by combining the antiferromagnetic MnNiGe martensite with ferromagnetic MnFeGe austenite, a magnetic-field-induced martensitic transformation has been achieved in MnNi1-xFexGe system. The doped Fe enables the isolated structural and magnetic transitions of MnNiGe to coincide at room temperature and also establishes ferromagnetic couplings in six-Mn-centering-one-Fe-atom clusters. The ferromagnetic clusters transit the antiferromagnetic state in martensite to a ferromagnetic state and the alloys are further induced to a stronger ferromagnetic state by external field, resulting in a large magnetization difference up to 50 emu/g across the transformation. The field-induced martensitic transformation thus experiences a multiple metamagnetization process.