Amorphous magnetic RE-Fe-Al alloys

Detail studies of the effects of rare-earth substitution on the magnetic pr operties of bulk amorphous hard magnetic NdE60Fe30Al10 alloys were carried out. Amorphous ribbons of alloys RE60Fe30Al10 (with RE = Nd, Sm, Gd and Dy) were prepared by melt-spinning at 30 m/s. As temperature increases, instea d of just a simple transition from ferromagnetic state to paramagnetic stat e, these ribbons undergo a superparamagnetic stage that ranges over about 1 00 K. Ribbons of alloys RE60Fe30Al10 with RE = Nd, Sm and Dy exhibit high v alues of coercivity (in MA/m) range at 4 K, while coercivity of ribbons of alloys with RE = Y and Gd remain low below 100 kA/m).