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 alloys 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 different positions and B is located in one type of site. The lattice constants, Curie temperature and saturation magnetization at 4.2K are determined. The mean field approximation yields a 4f-3d exchange integral of J(RCo)/k(B)=-20.9 K. The properties of these compounds are compared with those of R-Co alloys.