Martensitic Transformations and Magnetic-Field-Induced Strains in Ni_(50)Mn_(50-x)Ga_x Alloys

摘要

Concentration dependences of the temperatures of f orward and reverse martensitic transformations in Ni_(50)Mn_(50-x)Ga_x alloys (x = 19-25) and features of the jumpwise elongation e induced by magnetic field H in a single crystal of the Ni_(50)Mn_(28.5)Ga_(21.5) alloy have been studied. A single-variant state of martensite in the single crystal was formed by compression under the action of both a reference magnetic field and mechanical loading. It has been shown that when employing uniaxial mechanical compression, several large jumps (whose nature is associated with the appearance of structural defects hindering the displacement of boundaries of marten-site twins) arise in curves of the single-crystal elongation induced by an applied perpendicular magnetic field H_(perpendicular).