Structural phase transitions induced in Ni2MnGa by low-temperature uniaxial compression
Vasil'ev A. N. , Kaiper A., Kokorin V. V. , Chernenko V. A. , Takagi and J. Tani
The temperature dependence of the low-field magnetic susceptibility, the specific heat, and the transverse sound velocity has been measured in single crystals of the ferromagnet Ni2MnGa compressed along the (110) axis. The relative deformation was AL/L = 0.05. The load was removed at liquid-nitrogen temperature. The dimensions and shape of the crystals are restored upon heating as the result of a sequence of first-order structural phase transitions accompanied by clearly defined features on the curves of the physical properties studied. The new phases appear in Ni2MnGa because of an anomalous instability of the crystal lattice of this compound with respect to atomic displacements along a (MO) direction in the (110) plane.