Large magnetic-field-induced strains in Ni–Mn–Ga nonmodulated martensite

Large magnetic field-induced strains of up to 0.17% for a stress-free $Ni53.1Mn26.6Ga20.3$ single crystal with nonmodulated martensite phase were generated in a rotating magnetic field. This magnetic-field-induced strain, which is ten times larger than values reported so far for nonmodulated martensites, evidences significant magnetic-field-induced twin boundary motion, which so far was thought to be impossible. This result reinforces the interest in nonmodulated martensites, which are formed as a ground state in the Heusler-type ferromagnetic shape memory alloys.