Collapse of the Inverse Magnetocaloric Effect in the Ni47Mn40Sn13 Alloy in Cyclic Magnetic Fields

The results of direct measurements for the adiabatic temperature change ΔTad in the Ni47Mn40Sn13 alloy in cyclic magnetic fields by the magnetic field modulation method are presented. In the temperature dependence of the magnetocaloric effect (MCE), direct (ΔTad > 0) and inverse (ΔTad < 0) MCE are detected. The inverse effect value in a cyclic magnetic field depends on the temperature scanning rate. An increase in the frequency of a cyclic magnetic field with an induction of 1.2 T from 1 to 30 Hz decreases the direct effect value by more than 2 times. In a cyclic magnetic field with an induction of 1.2 T at frequencies f ≥ 1 Hz, complete disappearance (“collapse”) is observed for the inverse magnetocaloric effect, while ΔТad during the one-time actuation of magnetic field is –0.49 K. The dependence of the inverse effect value on the temperature scanning rate, along with its strong frequency dependence, results from both the manifestation of irreversibility in the magnetostructural phase transition due to hysteresis and the presence of phase inhomogeneities influencing the phase transition kinetics.