Magneto-optical Kerr effect in L10 FePdPt ternary alloys: Experiments and first-principles calculations

We have studied the magneto-optical Kerr effect (MOKE) of L10 Fe0.5(Pd1−xPtx)0.5 alloy films with both experiments and first-principles calculations. In the visible region, negative Kerr rotation and ellipticity peaks are, respectively, observed in the regions of 1.5–2.0 eV and 1.7–2.6 eV. These peaks are shifted towards higher energies, and their magnitudes are enhanced for larger x. The MOKE evolution is mainly ascribed to the anomalous Hall conductivity contributed by the spin-down d↓,x2−y2 bands from Pd and Pt. We established a close correlation among the MOKE spectra, the spin orbit coupling strength, and the band feature for this prototypical system.