Magnetic properties and magnetic reversal peculiarities of single crystals of R(Co1-xNix)5compounds

The basic properties (saturation moments, Curie temperatures, anisotropy constants) and magnetic reversal processes have been studied systematically on the bulk single crystals of quasibinary solid solutions R(Co1-xNix)5, where R = Y, La, Ce, Sm, and Gd. The magnetic reversals have been studied also on the single crystals of similar compounds with R = Nd, Dy, and Er. The general property of all studied systems is a very high coercive force Hcconnected with domain wall pinning in compounds of quasibinary region. The Hc(x) dependenses for all systems are similar qualitatively. There exists a maximum of Hcin region x = 0.6 - 0.7 for compounds with trivalent R, and in region x = 0.3 - 0.4 for compounds with tetravalent R. The single exception is the Gd system, where Hchas rather low values for all x. The explanation is suggested for Hc(x) dependence in which the compositional heterogeneities are considered as the main reason of domain wall pinning in the quasibinary compounds. These heterogeneities are always present as a result of statistical nature of Ni substitutions for Co.