Magnetic properties and large magnetocaloric effects in amorphous Gd-Al-Fe alloys for magnetic refrigeration

A series of the amorphous Gd(75-55)Al(25-5)Fe(0-40) alloy ribbons were prepared by melt spinning. The structure, magnetic properties and magnetocaloric effect (MCE) of these alloys were investigated. The prepared samples have shown the characteristics of a second-order phase transition with zero hysteresis loss and the T (c) can be tuned by changing the Fe contents. For the different compositions, the magnetic entropy change (-Delta S (m)) for a field change of 0-5 T reached a maximum value of 7.14 J kg(-1) K(-1) in the Gd(70)Al(20)Fe(10) alloy near its Curie temperature (T (c)) of 149 K. The non-linear composition dependence of (-Delta S (m)) could be caused by the competitions between Fe-Fe, Fe-Gd and Gd-Gd interactions. The refrigeration capacity (RC) values of these alloys are about 532-780 J/kg under a magnetic field change of 0-5 T. The results indicate that amorphous GdFeAl alloys can be considered as ideal candidates for a magnetic refrigerant in the temperature range of 104-222 K.