Kinetic arrest of martensitic transformation in Ni33.0Co 13.4Mn39.7Ga13.9 metamagnetic shape memory alloy

Abstract

Martensitic and magnetic properties of Ni33.0Co 13.4Mn39.7Ga13.9 metamagnetic shape memory alloy were investigated. The kinetic arrest phenomenon was observed at about 120 K by thermomagnetization measurements, and magnetic field-induced transformation (MFTT) was also detected at various temperatures ranging from 4.2 to 300 K. By evaluation of the equilibrium magnetic fields and temperatures based on the transformation fields and temperatures, it was confirmed that the transformation entropy change below 120 K becomes almost zero, which results in the kinetic arrest phenomenon. © 2010 The Japan Institute of Metals.