Magnetic anisotropy of L1-ordered FePt thin films studied by Fe and Pt L2,3-edges x-ray magnetic circular dichroism

Abstract

The strong perpendicular magnetic anisotropy of L1 0 -ordered FePt has been the subject of extensive studies for a long time. However, it is not known which element, Fe or Pt, mainly contributes to the magnetic anisotropy energy (MAE). We have investigated the anisotropy of the orbital magnetic moments of Fe 3d and Pt 5d electrons in L1 0 -ordered FePt thin films by Fe and Pt L 2,3 -edge x-ray magnetic circular dichroism (XMCD) measurements for samples with various degrees of long-range chemical order S. Fe L 2,3 -edge XMCD showed that the orbital magnetic moment was larger when the magnetic field was applied perpendicular to the film than parallel to it, and that the anisotropy of the orbital magnetic moment increased with S. Pt L 2,3 -edge XMCD also showed that the orbital magnetic moment was smaller when the magnetic field was applied perpendicular to the film than parallel to it, opposite to the Fe L 2,3 -edge XMCD results although the anisotropy of the orbital magnetic moment increases with S like the Fe edge. These results are qualitatively consistent with the first-principles calculation by Solovyev et al. [Phys. Rev. B 52, 13419 (1995).], which also predicts the dominant contributions of Pt 5d to the magnetic anisotropy energy rather than Fe 3d due to the strong spin-orbit coupling and the small spin splitting of the Pt 5d bands in L1 0 -ordered FePt.

Ultrafast demagnetization of Pt magnetic moment in L10-FePt probed by magnetic circular dichroism at a hard x-ray free electron laser

“…μ + and μ − are normalized to unity such that the polarization-averaged x-ray absorption is unity, i.e. respect to the edge jump was observed and are in good agreement with the results obtained using a synchrotron beamline [44]. TrXMCD measurements were performed at an x-ray energy of 11.567 keV, at which the Pt XMCD spectrum reaches the maximum.…”

“…It is known that the Fe magnetic moment dominates the total magnetic moment. It responsible for about 88% of the total moment [44]. To investigate the contribution of the Fe and Pt moments to the measured Kerr rotation, we have performed ab initio calculations of the MOKE spectrum [47], shown in figure 3(c), and the details are described in the appendix.…”

Induced versus intrinsic magnetic moments in ultrafast magnetization dynamics

“…We now turn to FePt on SiO2. Here, the magnetic moments on the Pt sites are induced by the exchange field of the intrinsic moments on the surrounding Fe sites [3,4,[32][33][34]. Figure 2b,c show the element-specific demagnetization and relaxation dynamics of FePt on SiO2 for a similar maximum quenching as for the CoFeB samples.…”

Detecting quadrupole: a hidden source of magnetic anisotropy for Manganese alloys

“…Positive values of E MCA stabilize the PMA. The second term becomes dominant when proximity-driven exchange split cases, such as the 4d and 5d states, are dominant 36,37 . In the case of Mn 3− δ Ga, the Mn 3d states were delicate regarding the mixing of the spin-up and -down states at the E F , which corresponds to the quadrupole formation and the band structure α values.…”