The effect of quenching and Mn substitution for Ni on the magnetic properties of Mn25+xNi50−xGa25

Abstract

Ni–Mn based Heusler alloys have attracted widespread attention due to their novel physical properties. However, the structure of Mn₂NiGa is metastable at room temperature, making it difficult to obtain its intrinsic physical properties and limiting its application. In this study, we obtained Mn₂NiGa by replacing Ni in the precursor alloy Ni₂MnGa with Mn and studied its magnetic properties, structures, and phase transitions with floating composition. In addition, we focused on the compositional segregation characteristics of Mn₂NiGa caused by different heat treatment and quenching conditions. It was found that the samples quenched after annealing at 773 K for 48 hours exhibited abnormalities in magnetism, phase transformation, and structure. The further electron probe scanning characterization results reveal that the changes in these physical properties were related to component segregation caused by heat treatment.