Temperature dependence of magnetically induced strain in single crystal samples of Ni–Mn–Ga

We investigate the effect of temperature and applied magnetic field on the strain behavior of oriented single crystal samples of Ni2MnGa. It is shown that the martensite twins can be partially oriented by the application of a magnetic field during cooling from the austenite state, observing a strain of the order of 1%. Depending on the final cooling temperature, a different value of magnetically induced strain is observed in the martensite phase, an effect due to the irreversible alignment of a fraction of the martensite twins to the magnetic field direction. The results are discussed with reference to different experimental procedures and the shape memory characteristics of the alloy