Premartensitic phase transformation in the Ni2MnGa shape memory alloy

We present a phenomenological model for the premartensitic phase transition in ferromagnetic NiMnGa alloys. The model contemplates the effects of an applied mechanical stress on the premartensitic transition. It is shown that the premartensitic transition is driven by a magnetoelastic coupling. The first order character of this transition is enhanced by the application of a mechanical stress. Experimental data are also presented which support the predictions of the proposed model.