Structure and magnetic properties of melt-spun Nd2Fe14B/α-Fe/NdCu2 ribbons

Partially amorphous ribbons were prepared by melt-spinning from a Nd-Fe-B alloy containing 10 wt.% Cu. Their crystallization behaviour as well as their magnetic properties were investigated. During annealing three phases are formed: the majority phase Nd2Fe14B, α-Fe, and additionally NdCu2. After an optimal heat treatment at 570 °C for 30 min a coercivity of μ0HcJ = 0.32 T, a remanence of Br = 0.74 T and a saturation polarization of Js = 1.18 T are obtained. The comparison of demagnetization curves of samples annealed at different temperatures reveals a decrease of exchange interaction between the soft and the hard magnetic phase with increasing annealing temperature.