Magnetic anisotropy of FePt: Effect of lattice distortion and chemical disorder

Abstract

We perform first principles calculations of the magnetocrystalline anisotropy energy (MAE) in the five samples of L10 FePt that were studied experimentally by Ding and co-workers [J. Appl. Phys. 97, 10H303 (2005)]. The effect of temperature-induced spin fluctuations is estimated by scaling the MAE down according to previous Langevin dynamics simulations. Including chemical disorder as given in experiment, the experimental correlation between the MAE and the lattice mismatch is qualitatively well reproduced. Moreover, we determine the chemical order parameters that reproduce exactly the experimental MAE of each of the samples. Our observations lead to the conclusion that the MAE of the FePt samples is determined by the chemical disorder rather than by lattice distortion. © 2011 American Institute of Physics.