Effect of low dc magnetic field on the premartensitic phase transition temperature of ferromagnetic Ni2MnGa single crystals

The temperature and field dependence of alternating-current (ac) susceptibi lity in a Ni50Mn25Ga25 single crystal was measured using an ac susceptomete r with a de magnetic field oriented in the [100] and [110] directions, resp ectively. It is found that even at very low fields the premartensitic trans ition temperature decreases monotonically with the increase of the applied field, and it decreases more rapidly with field applied along the [110] dir ection than with field along the [100] direction, In accord with a previous model, present results confirm that the magnetoelastic interaction is resp onsible for the premartensitic transition, and the magnitude of the magneto elastic interaction in the [110] direction is stronger than that in the [10 0] direction.