Spin-axis-dependent magnetic properties of FePt and CoPt

A theoretical study of the magnetic properties of the CoPt and FePt ordered alloys has been performed. The calculation is done as a function of the spin-quantization axis by means of both the local spin density and the generalized-gradient approximations in conjunction with the full-potential linear muffin-tin orbital method. Both approximations produced similar results for the FePt and CoPt compounds. The band structure and the total density of states have been calculated and it was confirmed that all electronic states contribute to the magneto-crystalline anisotropy energy; the magnetization axis is along the [001] direction. The Fe and Co orbital magnetic moments decrease with respect to the angle gamma between the [001] axis and the spin quantization axis, but for the [100] axis the orbital moment is comparable to the [001] moment. The Pt orbital moments are of the same order of magnitude as those of Fe and Co moments due to the large spin-orbit splitting parameter of Pt and show a similar behavior with the angle T. (C) 2002 Elsevier Science B.V. All rights reserved.