Ab initio study of half-metal to metal transition in magnetite
Abstract
We analyze the influence of conditions (stress, substitutional dopants) that induce a half-metal to metal transition leading to a loss of the material's desirable half-metallic properties. Total energies, electronic structure, and magnetic moments are calculated by DFT using the FLAPW method. Results obtained within the generalized gradient approximation show excellent agreement with experimental findings. In response to uniaxial, biaxial or triaxial pressure, a half-metal to metal transition occurs, which shifts the Fermi energy from the gap of the majority-spin electrons under the top of the valence band so that both spin channels become metallic. We also performed a total-energy analysis of five different structural and spin configurations simulating the substitution Fe_2.5X_0.5O4 (X = Mn, Co, Ni). The lowest-energy configurations are in good agreement with experimental observations. For Mn substitution we find a metallic character but Co and Ni doped crystals are predicted to be half-metals.
- Publication:
-
APS March Meeting Abstracts
- Pub Date:
- March 2004
- Bibcode:
- 2004APS..MARV24005F