| Popis: |
Band structure calculations and magnetic measurements were performed on (Gd x Y 1− x )Co 4 Si as well as on YCo 4 M compounds, where M = Ga, Al, and Co. The substitutions both at rare-earth and cobalt sites influence strongly the cobalt moments as well as the Curie temperatures. When Y is replaced by Gd, in Gd x Y 1− x Co 4 Si system, the mean cobalt moments increase from 0.73 μ B /atom to 1.25 μ B /atom. The computed magnetic moments per formula unit agree rather well with experimental data. The reciprocal susceptibilities for ferrimagnetic compounds show non-linear temperature dependences. The effective cobalt moments are little dependent on composition. The ratio r between the mean number of cobalt spins determined from effective and saturation cobalt moments, respectively follows a dependence on Curie temperature of the form r ∝ T c − 2 / 3 . The magnetic behaviour of cobalt is analysed in spin fluctuations model. |
Full Text from ScienceDirect