Magnetic Properties of the RCo4B Compounds (R=Y, Pr, Nd, Sm, Gd, Tb)

The RCo4B (R=rare earth) compounds crystallize with the CeCo4B-type structure. They are obtained by an ordered substitution of cobalt by boron in every second layer of the CaCu5 structure. We report on a study of the structural and magnetic properties of the RCo4B with different rare-earth elements (R=Y, Pr, Nd, Sm, Gd, Tb). The c lattice parameter of the hexagonal structure remains almost constant, while the a parameter goes up when the atomic radius of the rare-earth element increases. The compounds with R=Y, Pr, and Nd are ferromagnetically ordered, whereas the compounds with Gd and Tb are ferrimagnetic. We also present the evolution of the easy magnetization direction depending on R at room temperature. The ordering temperatures are presented and the saturation magnetization at both temperatures 5 and 300 K are discussed for each compound.