The Large Magnetocaloric Effect in Amorphous Fe_80-xMn_xZr₁₀(x = 4,6,8,10) Alloys

The Magnetization behaviour has been measured for amorphous $Fe_80-xMn_xZr₁₀$ (x = 4,6,8,10) alloys. The Curie temperature decreased from 236 K to 195 K with increasing Mn concentration (x = 4 to x = 10). 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 $T_c$ where the mean magnetic moment of the superparamagnetic spin clusters decreased with increasing temperature. A large magnetic entropy change, ${\Delta}S_M$, which is calculated from H vs M curves associated with the ferromagnetic-paramagnetic transitions in amorphous, has been observed. With Mn concentration increasing, ${\Delta}S_M$ decreases 1.04, 0.95, 0.87 J/kg K at 222, 210, 195 K (the Curie temperature), respectively.