First principles calculations of the hyperfine field at Gd nuclei in intermetallic compounds

Self-consistent scalar relativistic band structure calculations have been performed to calculate the hyperfine field at the Gd nucleus in elemental hcp Gd and in a large number of intermetallic compounds including GdCo₅, Gd₂Fe₁₇, Gd₂Fe₁₇N₃ and Gd₂Fe₁₄B. The wide range of experimentally observed hyperfine fields is explained adequately by the theory. However, the calculated and experimental hyperfine fields differ systematically by an overall shift of approximately 25 T. To a good approximation the hyperfine field is linearly related to the Gd 6s partial magnetic moment.