Anomaly in entropy change between parent and martensite phases in the Ni50Mn34In16 Heusler alloy

Magnetic change due to the martensitic transformation induced by high magnetic fields up to 18 T was investigated in the Ni50Mn34In16 metamagnetic shape memory alloy. Kinetic arrest of the martensitic transformation was observed and the martensitic transformation no longer proceeded at temperatures below around 100 K. The transformation entropy change between the martensite phase and parent phase evaluated from the magnetization curves showed an unusual behavior, changing from positive to negative at about 80 K. (C) 2008 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.