Angular dependence of coercive field in (Sm,Zr)(Co,Cu,Fe) sub(z) alloys

The angular dependence of the coercive force, H sub(c)( psi ), has been studied systematically for a variety of quasi-single-crystal spherical samples of non-stoichiometric Sm sub(0.85)Zr sub(0.15)(Co sub(0.7)Cu sub(0.09)Fe sub(0.21)) sub(z) alloys (z identical with 6.1, 6.4 and 6.7), for which possible effects of grain misalignment and nonuniform self-demagnetizing field are avoided. The observed H sub(c)( psi ) variation agrees well with the model based on Neel's phase theory, which predicts a maximum in the H sub(c)( psi ) curve followed by a decrease to zero for psi identical with pi /2, provided the samples have a narrow H sub(c) distribution. Heat treatments resulting in a wide H sub(c) distribution lead to a variety of rather exotic H sub(c)( psi ) shapes which are explained by the appearance of cooperating low-anisotropy phases in these non-stoichiometric compounds.