A dislocation model for the magnetic field induced shape memory effect in Ni2MnGa

The magnetically driven shape memory effect in Ni2MnGa body-centered tetragonal martensite is onset by the motion of 0.144 〈1 1 1〉 type twin dislocations on the {1 1 2} type planes. Calculations show that the application of a 400 kA/m magnetic field can induce a shear stress of approximately 2.8 MPa on these twin dislocations, a value exceeding the Peierls and the yield stress for Ni2MnGa.