Second-order anisotropy due to magnetostriction for L10-FePt

Abstract

The effective magnetocrystalline anisotropy energy associated with magnetostriction is studied for tetragonal L10-FePt by means of first-principles calculations, which is expressed in terms of the intrinsic anisotropy for an undeformed crystal, the magnetostrictive coefficients, and the elastic tensor. A very small correction is found for the first anisotropy constant Delta K1/K1 = 0 . 07 %, while a much more significant contribution is obtained for the second one Delta K2/K2 = 21.86%. General analysis of this effect for tetragonal crystals is provided, finding that Delta K1 will be always positive for any stable phase with this symmetry. The potential implications and applications of these results are discussed.