Magnetic properties of the RCo4B compounds (R = Y, Pr, Nd, Sm, Gd, Tb)

The RCo4B (R = rare earth) compounds crystallize with the CeCo4B-type struc ture, They are obtained by an ordered substitution of cobalt by boron in ev ery second layer of the CaCu5 structure. We report on a study of the struct ural and magnetic properties of the RCo4B with different rare-earth element s (R = Y, Pr, Nd, Sm, Gd, Tb), The c lattice parameter of the hexagonal str ucture remains almost constant, while the a parameter goes up when the atom ic radius of the rare-earth element increases. The compounds with R = Y, Pr , and Nd are ferromagnetically ordered, whereas the compounds with Gd and T b are ferrimagnetic, We also present the evolution of the easy magnetizatio n direction depending on R at room temperature, The ordering temperatures a re presented and the saturation magnetization at both temperatures 5 and 30 0 K are discussed for each compound. (C) 2000 Academic Press.