ELECTRONIC-STRUCTURE, MAGNETISM, AND FERMI SURFACES OF GD AND TB

We report on local-spin-density calculations for the ferromagnetic rar e-earth metals Gd and Tb using the relativistic first-principles linea r-muffin-tin-orbital method in the atomic-sphere approximation. We hav e used a method which treats simultaneously the localized 4f and the c onduction electron spin magnetism. The 4f magnetic moments are obtaine d from the Russel-Saunders scheme but the radial 4f spin density is a part of the self-consistent density-functional calculations. The calcu lated conduction-electron moment for Gd is in very good agreement with the measured value. The calculated de Haas-van Alphen frequencies are in agreement with available data.