Magnetocaloric properties of amorphous GdNiAl obtained by mechanical grinding

An amorphous GdNiAl sample was prepared by mechanical grinding performed on a crystallised intermetallic. The treatment changes greatly the ferromagnetic behaviour of this compound; its Curie temperature decreases from 57 K (unmilled sample) to 29 K ( milled sample). Specific heat and magnetisation measurements reveal that amorphous GdNiAl exhibits an interesting magnetocaloric effect; for an applied magnetic field of 5 T a change of congruent to 8.9 J/kg K is observed at 36 K for the isothermal magnetic entropy.