Magnetocaloric effect and magnetization in a Ni-Mn-Ga Heusler alloy in the vicinity of magnetostructural transition

TL;DR

This study investigates the magnetocaloric and magnetic properties of a Ni-Mn-Ga alloy near its coupled magnetostructural transition, combining experimental measurements with a new statistical model to describe phase coexistence.

Contribution

The paper introduces a statistical model that accounts for martensite and austenite coexistence to describe properties near the magnetostructural transition.

Findings

Measured magnetocaloric effect near transition temperature.

Developed a theoretical model for phase coexistence.

Observed significant magnetocaloric response in the alloy.

Abstract

The magnetic and thermodynamic properties of a Ni2.19Mn0.81Ga alloy with coupled magnetic and structural (martensitic) phase transitions were studied experimentally and theoretically. The magnetocaloric effect was measured by a direct method in magnetic fields 0-26 kOe at temperatures close to the magnetostructural transition temperature. For theoretical description of the alloy properties near the magnetostructural transition a statistical model is suggested, that takes into account the coexistence of martensite and austenite domains in the vicinity of martensite transformation point.