CRYSTALLOGRAPHIC AND MAGNETIC-PROPERTIES OF R3CO11B4 (R=Y AND GD) COMPOUNDS

The structure and magnetic properties of R3Co11B4 compounds, where R=Y and Gd are investigated. X-ray analysis reveals that the R3Co11B4 all oys crystallize in the hexagonal Ce3Co11B4 structure. The unit cell of the structure contains 18 atoms. The rare earth atoms are distributed in. two different crystallographic sites, the Co atoms in three diffe rent positions and B is located in one type of site. The lattice const ants, Curie temperature and saturation magnetization at 4.2K are deter mined. The mean field approximation yields a 4f-3d exchange integral o f J(RCo)/k(B)=-20.9 K. The properties of these compounds are compared with those of R-Co alloys.