2010 Volume 51 Issue 7 Pages 1357-1360
Magnetic properties and martensitic transformation behaviors of NiCoMnAl metamagnetic shape memory alloys were investigated. The kinetic arrest phenomenon was observed at about 40 K during thermomagnetization measurements. At temperatures ranging from 4.2 to 200 K, magnetic field-induced reverse transformation was confirmed by a pulse magnetometer with a magnetic field up to 45 T. By plotting the equilibrium magnetic fields against the measured temperature, the transformation entropy change was calculated by using the Clausius-Clapeyron equation. The transformation entropy change was found to become zero below 40 K, which can explain the appearance of the kinetic arrest phenomenon.