Properties of sputter-deposited Ni-Mn-Ga thin films

Sub-micrometer Ni-Mn-Ga films on MgO(0 0 1) single-crystalline wafers have been prepared by radio-frequency magnetron sputtering. The structural and magnetic states of the as-received (quasi-amorphous phase) and annealed (highly ordered martensitic phase at T = 300 K) films have been examined by X-ray diffraction, and measurements of resistivity and magnetization. The annealed films demonstrate a transformation behavior typical for the bulk and show a thickness dependence of the magnetic properties.