Role of the Temperature Dependence of Elastic Modulus in the Basic Characteristics of Giant Magnetically Induced Deformation of Ferromagnetic Martensite

Abstract

The experimental temperature dependence of threshold magnetic field initiating the giant magnetically induced deformation of Ni-Mn-Ga martensitic alloy has been analyzed. The relationships between the temperature dependences of threshold magnetic field, magnetostriction and elastic modulus have been revealed and described theoretically. It has been shown that the temperature limits of giant magnetically induced deformation and the character of temperature dependence of threshold magnetic field are predetermined by the temperature dependence of soft elastic modulus of alloy in the martensitic phase. It has been demonstrated that the careful fitting of theoretical temperature dependence of threshold field to the experimental one results in the characterization of hardly measurable physical values of martensitic phase, such as temperature dependences of elastic modulus and magnetostriction.