Magnetic hyperfine fields at sp-impurities in cobalt and nickel
Heinz Haas;
The understanding of magnetic hyperfine fields (B hf) at impurity nuclei in magnetic materials has been a central problem in nuclear solid state physics for the last decades. Recent progress in density functional calculations has enabled a virtually quantitative description ofB hf at substitutional impurities in iron with the supercell approach. The present calculations were performed in an equivalent manner for the sp elements Fe-Kr, Ru-Xe, and Os-Rn in the other two simple ferromagnetic matrices, Co and Ni. The used M15X cell in optimized geometry allows for volume expansion and nearest neighbor relaxation. For Co the China magnets experimentalB hf data are quite well reproduced, though there are some remaining discrepancies at the end of the series. For Ni the qualitative trends are also accounted for, but the quantitative agreement is not satisfactory. Increasing the supercell size to Ni127X for the 5sp impurities does not lead to much better results.http://www.chinamagnets.biz
