Microstructure and magnetic properties of Ni50Mn37Sn13 Heusler alloy ribbons

The Heusler alloy Ni50Mn37Sn13 was successfully produced as ribbon flakes of thickness around 7-10 mu m melt spinning. Fracture cross section micrographs in the ribbon show the formation of a microcrystalline columnarlike microstructure, with their longer axes perpendicular to the ribbon plane. Phase transition temperatures of the martensite-austenite transformation were found to be M-S=218 K, M-f=207 K, A(S)=224 K, and A(f)=232 K; the thermal hysteresis of the transformation is 15 K. Ferromagnetic L2(1) bcc austenite phase shows a Curie point of 313 K, with cell parameter a=0.5971(5) nm at 298 K, transforming into a modulated 7M orthorhombic martensite with a=0.6121(7) nm, b=0.6058(8) nm, and c=0.5660(2) nm, at 150 K. (C) 2008 American Institute of Physics.