Observation of field-induced reverse transformation in ferromagnetic shape memory alloy Ni50Mn36Sn14

The structural and magnetic properties of the ferromagnetic Heusler alloy Ni50Mn36Sn14 were studied by magnetization and x-ray powder diffraction measurements in fields up to 5 T. The alloy undergoes the martensitic transformation from the L2(1)-type cubic structure with the lattice parameter a(c)=0.5988 nm into an orthorhombic structure with the lattice parameters a(o)=0.8617 nm, b(o)=0.5702 nm and c(o)=0.4359 nm at M-s=220 K with a thermal hysteresis of 40 K. The cell volume contracts by 0.37% and the magnetic moment decreases by 50% at M-s. Furthermore, we directly observed the field-induced reverse martensitic transformation. (c) 2006 American Institute of Physics.