High-temperature magnetic shape memory actuation in a Ni–Mn–Ga single crystal

  We report a Ni–Mn–Ga single crystal that demonstrates giant magnetic field-induced strain of 7.3% at room temperature and of 4.5% at 80 °C. This is the highest temperature at which strain caused by twin boundary motion induced by an external magnetic field has been reported. A dedicated testing bench was constructed for the high-temperature experiments. X-ray diffraction reveals that at room temperature the material possesses a mixture of 5M and of 7M martensites, while at 80 °C the 5M structure predominates.