FORMATION AND MAGNETIC-PROPERTIES OF R(2)FE(17-X)GA(X)C(2) COMPOUNDS PREPARED BY ARC-MELTING

The single phase compounds of R(2)Fe(l7_x)Ga(x)C(2)(R = Y, Nd, Sm, Gd, Tb, Dy, Ho, Er and Tm; x = 2 and 3) with the rhombohedral Th2Zn17-type or hexagonal Th2Ni17-type structures were prepared by arc-melting. Their formation, structure and magnetic properties were studied. The substitution of Ga in the R(2)Fe(17)C(2) results in the increase of unit cell volume and the decrease of saturation magnetization. Curie temperatures have a small change when x I 2, then decrease with x. The Sm2Fe17_xGaxC2 compounds with x = 2 and 3 are found to have a uniaxial magnetocrystalline anisotropy and show a room-temperature anisotropy field of 95 and 93 kOe, respectively. Spin reorientation transitions are observed in the Er2Fe17_xGaxC2 and Tm2Fel7_xGaxC2 compounds. The substitution of Ga for some Fe in the R(2)Fe(l7)C(2) compounds with R = Er and Tm increases the uniaxial anisotropy of the R sublattices, resulting in the increase of spin reorientation temperature.