HYPERFINE FIELD ANISOTROPY AND SPIN REORIENTATION IN TERNARY CARBIDES OF THE TYPE R2FE17CX

The compounds Sm2Fe17Cx and Er2Fe17Cx were investigated using 57Fe Mössbauer spectroscopy at various temperatures. The compound Er2Fe17C gives rise to a spin reorientation at TSR = 82 K, at which temperature the easy magnetization direction changes from perpendicular to the c axis (T > 82 K) to parallel to the c axis (T < 82 K). Owing to a strong hyperfine field anisotropy, the temperature dependence of the effective hyperfine field shows a discontinuity which is fairly pronounced for the dumb-bell iron site in particular. From magnetic measurements it was derived that the Curie temperature increases significantly with x in Sm2Fe17Cx. In Sm2Fe17C no spin reorientation was observed, showing that the easy magnetization remains parallel to the c axis up to the Curie temperature. © 1990.