Epitaxial Ni-Mn-Ga films deposited on SrTiO_3 and evidence of magnetically induced reorientation of martensitic variants at room temperature

摘要

Epitaxial Ni-Mn-Ga films were grown on SrTiO_3 by sputter deposition. The films deposited at 673 K are ferromagnetic and martensitic at room temperature. Pole figure measurements indicate that the twinned orthorhombic martensite microstructure of the film has a lower symmetry compared to bulk. Magnetically induced reorientation or magnetic shape memory effect is indicated by magnetization curve measurements. Though the overall extension of the film is constrained by a rigid substrate, the reorientation is possible due to the additional degree of freedom in the orthorhombic phase.