Glass forming ability and magnetic characteristics of rare earth - Transition metal alloys

Abstract

Effects of various substitutions on glass forming ability (GFA) and hard magnetic properties of bulk amorphous alloy Nd60Fe30Al10 were studied. RE60TM30MT10 alloys with RE = Nd, Sm, Dy, Gd, TM = Fe, Co and MT = Al, B, Si were prepared. Only substitutions by B and Si retained both the good GFA and hard magnetic properties at room temperature. Fully amorphous alloy Sm60Co30Al10 was paramagnetic at room temperature. Unique series of magnetic transitions from paramagnetic to superparamagnetic and then to ferromagnetic state as temperature decreased were observed for melt-spun ribbons of alloys Sm60Fe30Al10, Dy60Fe30Al10 and Gd60Fe30Al10. Cluster Ferromagnetism Model was developed to describe the magnetic behavior of these alloys. Alloy Nd60Fe10Al10 exhibit the highest transition temperatures. GFA and magnetic properties of alloys around eutectic composition of Nd-Fe-B, Nd-Fe-Al and Sm-Co-Al system were studied. GFA and hard magnetic properties improved as composition of Nd-Fe-Al alloys deviated from eutectic Nd80.5Fe7.5Al12 towards Nd60Fe30Al10.