Kinetic effects in the magnetic and magnetocaloric properties of metamagnetic Ni50Mn35In14.25B0.75

Ni50Mn35In14.25B0.75 is a typical representative of the family of metamagnetic In-based Heusler alloys which shows large magnetocaloric effects generated from first order magnetostructural and ferromagnetic-paramagnetic transitions. For this alloy, a study of the adiabatic temperature change ΔTad by a direct method and through thermomagnetic measurements in magnetic fields up to 14 T has been performed. It has been shown that the rate of heating/cooling can affect the magnitude and sign of ΔTad. The application of magnetic fields larger than 12 T (on cooling) results in the “kinetic arrest” of the ferromagnetic austenitic phase. The effects of the temperature and magnetic history, and kinetic effects, on ΔTad of these Ni-Mn-In-based Heusler alloys in high magnetic fields are discussed.