ELECTRONIC BAND STRUCTURES OF ANTIFERROMAGNETIC ORDERED ALLOY FePt3

Abstract

The electronic band structures of an ordered alloy FePt3, having the Cu3Au-type crystal structure, are calculated by using a self-consistent augmented plane wave (APW) method for both non-magnetic (NM) and antiferromagnetic (AF) states. For the NM state, the conduction bands near the Fermi level are hybridized bands which are mainly composed of Fe 3d and Pt 5d orbitals. The Fermi surface shows clearly the nesting feature for the wavevector Q=(π/a, π/a, 0), which would be responsible for the stabilization of the observed AF structure. For the AF state, a large energy splitting of about 4 eV between the spin-up and spin-down bands is found for only Fe 3d states. The magnetic moment at Fe sites is obtained as 3.3µB/Fe, which agrees well with the observed value of 3.3µB/Fe. By comparing the joint densities of states, the difference in optical spectra between the NM and the AF states is clarified.