Abstract
Isotropic Nd15(Fe1−xCox)77B8 ribbons are produced by conventional melt spinning. For moderate Co additions the coercivity HcI increases while the remanence Jr remains almost constant. Co contents above x=0.3 lead to decreasing HcI and Jr values. The beneficial effect of Co on coercivity is ascribed to the occurrence of a Nd‐Fe‐Co minority phase which serves as pinning center for domain walls. The temperature characteristic of the coercivity and the remanence is substantially improved due to the increased Curie temperature Tc and the pinning‐type behavior of the material.