Effect of compressive load on magnetic shape memory effect in Ni-Mn-Ga single crystal

Abstract

We investigated the effect of large compressive stress on magnetic shape memory effect in modulated 10M martensite of Ni-Mn-Ga Heusler alloy. The single crystalline sample deformed approximately elastically up to highest load 540 MPa. Structural and microstructural changes of a single crystal were analysed by X-ray diffraction 2D scan mapping in 2θ and ω. Although the crystal structure, lattice cell parameters, and twinned microstructure (a/b and modulation twinning) exhibited only small changes after the loading, the volume of the sample undergoing the magnetically induced reorientation decreased sharply while magnetic field necessary for the reorientation gradually increased. The extrapolation suggested that no magnetically induced reorientation might occur after compression of about 1 GPa.