Exchange and crystal field interactions in RCo4B (R  Gd, Dy, Ho, Er)

Abstract

The exchange and crystalline-electric field effects in RCo4B compounds with heavy rare earth are analysed using a series of experiments. These experiments include magnetic moment behaviour, Curie temperature, temperature dependence of magnetocrystalline anisotropy and reorientation of spin magnetization in Ho and Dy compounds. The molecular field coefficient nRCo is evaluated from temperature dependence of magnetization in two-sublattice model and from the analysis of the Curie temperature. The latter depends on the nature of the rare earth. The value of the RCo exchange field is discussed. The magnetocrystalline anisotropy behaviour is treated in terms of the exchange and crystal field interactions which may differ at a and b sites. The increase of the crystal effects in comparison with RCo5 compounds results in a reduction of the 4f magnetocrystalline anisotropy especially for the b site.