Martensite Transformation, Magnetotransport Properties, and Magnetocaloric Effect in Ni47Mn42In11 Alloy

The structure, electric properties, and magnetocaloric effect in Ni47Mn42In11 ferromagnetic alloy in which the martensite transformation temperature is close to room temperature and nearly coincides with the austenite Curie temperature are studied. It is revealed that the spontaneous transformation of martensite to austenite is accompanied with the decrease by 45% in its resistivity. In the martensite transformation induced by a magnetic field, a negative magnetoresistance is observed; it reaches ≈15% in the magnetic field with a strength of 18 kOe. The temperature dependence of the maximum change in the entropy in the martensite transformation induced by the magnetic field was calculated by using the Clausius–Clapeyron equation. It is shown that the maximum values of the magnetoresistance and magnetocaloric effect are observed near the temperature of the spontaneous martensite transformation.