Magnetic properties and crystallization of amorphous Fe-Nd-B alloys at constant Nd concentration

Abstract

The B-content dependence of magnetization, Curie temperature, and crystallization temperature for amorphous (Fe1−xBx)100−yNdy alloys with y=4, 7, and 12 were studied. Spontaneous magnetization shows a monotonic decrease with x, and the noncollinear spin structures have been proposed to explain the observed results. It is found that the Curie temperature of the samples increases at first with increasing B concentration x, and shows a maximum value at a certain B concentration, then decreases monotonically with x. The composition dependence of Tc is explained by the average molecular-field model. An exceptionally strong rise of crystallization temperature with x is found, and demonstrates that the thermal stability of amorphous Fe-Nd-B alloys has a remarkable enhancement by the substitution of B for Fe.