The magnetic entropy change on amorphous FeMnZr alloys

The magnetization behaviors have been measured for amorphous Fe90-xMnxZr10 (x=0, 4, 6) alloys. The Curie temperature is decreased from 243 to 218K with increasing Mn concentration (x =0-6). The magnetization measurements were conducted at temperatures above the Curie temperature in the paramagnetic region. In all samples, the magnetic properties showed superparamagnetic behavior above Tc where the mean magnetic moment of the superparamagnetic spin clusters decreased with increasing temperature. A large magnetic entropy change DSM, which is calculated from H vs. M curves associated with the ferromagnetic-paramagnetic transitions in amorphous state, has been observed. The maximum of DSM was found to appear in the vicinity of the Curie temperature of the amorphous phase. The value is 2.96, 2.51 and 2.29 J/kg K at x = 0, 4 and 6, respectively. (C) 2006 Elsevier B. V. All rights reserved.