The anomalous staircase-like magnetization behavior and giant magnetocaloric effect in a Fe–Mn-Ga magnetic shape memory alloy

The anomalous staircase-like magnetization behavior has been investigated in a Fe–Mn-Ga magnetic shape memory alloy. Here, we elucidate the underlying mechanism for such anomalous magnetic behavior is caused by the magnetic-field-induced structural transformation occurring at low temperature. The reversal of structural phase transformation in a sufficient thermodynamics area is accounted for the abrupt changes of the magnetization behavior. Moreover, a giant magnetocaloric effect with isothermal entropy change of ~60 J kg⁻¹K⁻¹ under 5 T magnetic field was discovered, which is due to the antiferromagnetic to ferromagnetic transition, different from the previous report in magnetic shape memory alloys. The present work provides insights into the interplay between magnetism and structure in magnetic shape memory alloys, and instructive understanding of the anomalous staircase-like magnetization behavior in other materials undergoing a magnetostructural transition.