Thermal and Magnetic Properties of Stress-Induced Martensites in Ni-Mn-Ga Alloys

Abstract

The stress-induced transformation of single crystals of Ni-Mn-Gaferromagnetic Heusler ordered alloys to new martensitic structures hasbeen investigated. The intermartensitic transformations, whenever theyoccur, were registered during heating by calorimetry, dilatometry andmagnetic susceptibility measurement, showing up a step-like strainrecovery, small endothermal effects, and an abrupt change of thelow-field magnetic susceptibility. During intermartensitictransformations, between modulated and unmodulated lattices, as well asduring the final transformation to the parent austenitic phase,noticeable anomalous changes in the specific magnetization wereobserved.