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

Abstract The magnetic and thermodynamic properties of a Ni 2.19 Mn 0.81 Ga 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.