High Field Magnetization

The Heusler shape memory alloys undergo an austenite to martensite structural transition, accompanied by a large change in the magnetic structure. A field induced magnetostructural transition can be observed near to the martensitic transition temperature. Sometime they show a field-induced irreversibility near the martensitic transition due to a partial or complete arrest of the supercooled austenite phase. The irreversible behavior becomes less pronounced by moving away from the transition temperature and vanishes at a finite temperature when measured in a finite field available in the lab. With help of pulsed magnetic field study on different families of Heusler shape memory alloys, we demonstrate the existence of a field-induced irreversibility at temperature much below the martensitic transition. This irreversibility can lead to a hysteresis width as large as 24 T in some of these materials [1].

Figure 1: 60T pulsed field magnetization study in shape memory alloys.

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