Degradation of the magnetocaloric effect in Ni$_{49.3}$Mn$_{40.4}$In$_{10.3}$ in a cyclic magnetic field

The direct measurements of the magnetocaloric effect $\Delta T_{\operatorname{ad}}$ in the Heusler alloy Ni$_{49.3}$Mn$_{40.4}$In$_{10.3}$ have been carried out in cyclic magnetic fields with amplitudes to 8 T. The maximum values of the magnetocaloric effect are 5.29 K in the martensite–austenite transition region and 3.39 K in the region of the magnetic phase transition in the austenite phase. A long-term action of a cyclic magnetic field is shown to lead to a marked decrease in the value of the magnetocaloric effect in the region of the magnetostructural martensite–austenite transition. The initial properties are recovered after the complete transition of the sample to the austenite phase. The phenomenon observed in this study restricts the application of these materials in the magnetic cooling technology.