Abstract
Electronic structures and magnetism of the nonoxide perovskite compounds , 1, 2, and 3; and Fe), based on recently found superconducting have been investigated with first-principles all-electron full-potential linearized augmented plane-wave calculations within the local-(spin) density approximation. From the results of total-energy calculations, it is expected that (i) the suppression of superconductivity occurs faster for the Fe-doped case than for the Co-doped case with increase of x, and (ii) ferromagnetic transitions occur when for the Co-doped cases, while the Fe-doped cases become ferromagnetic before From the calculated density of states, it is found that the superconductor becomes paramagnetic and then ferromagnetic, as we increase the number of minority spin d-band holes via Co and Fe doping at Ni sites. A hypothetical system, MgC(FeCoNi), has also been calculated and found to be ferromagnetic with magnetic moments of and for Fe, Co, and Ni, respectively, which are roughly proportional to the number of d-band holes of minority spin. These features are well explained by d-band spin splitting, as in conventional metallic ferromagnets.
- Received 9 August 2001
DOI:https://doi.org/10.1103/PhysRevB.65.064525
©2002 American Physical Society