Hysteresis effects in the magnetic-field-induced reverse martensitic transition in magnetic shape-memory alloys

摘要

We study the mechanism of magnetic-field-induced reverse martensitic transformations by considering the field-induced temperature-shifts in the thermal hysteresis loop of the magnetization and critical fields determined from magnetization isotherms. We consider first the temperature-shifts in a symmetric thermal hysteresis loop and extend the discussion to the case of the Heusler-based Ni_(50)Mn_(34)In_(16) magnetically superelastic alloy having a nonsymmetric thermal hysteresis loop. We obtain two different temperature-behaviors for the critical field depending on whether the initial measurement temperature lies on the forward or on the reverse transformation path of the thermal hysteresis.