Crystallographic and Magnetic Properties of R_(2) Fe_(17)C_(x) with R=Y, Pr, Nd, Sm, Gd, Dy, and Er

摘要

A series of R_(2) Fe_(17)C_(x) compounds(R=Y,Pr,Nd,Sm,Gd,Dy,and Er;x=0,0.5 and 1.0)were synthesized.X-ray diffraction analyses showed that the crystal structure is rhombohedral Th_(2)Zn_(17) type for R=Pr,Nd,Sm,and Gd.For R=Y,Dy and Er,a structure transformation from hexagonal Th_(2)Ni_(17) type(x=0.5)to rhombohedral Th_(2)Zn_(17) type(x=1.0)was observed.The introduction of C into R_(2)Fe_(17) leads to an expansion of the lattice.It strongly enhances Curie temperature.C atoms occupy interstitially the nearest neighbour sites to the R atoms in the lattice.The anisotropy of R sublattice was strengthened.A uniaxial anisotropy was observed in Sm_(2)Fe_(17)C_(0.5) at room temperature.