Microstructure and magnetic properties of Ni{sub 50}Mn{sub 37}Sn{sub 13} Heusler alloy ribbons

The Heusler alloy Ni{sub 50}Mn{sub 37}Sn{sub 13} 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{sub S}=218 K, M{sub f}=207 K, A{sub S}=224 K, and A{sub f}=232 K; the thermal hysteresis of the transformation is 15 K. Ferromagnetic L2{sub 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.