Magneto optical kerr spectroscopy as a probe of chemical ordering in CoPt

Abstract

We demonstrate that the photon energy dependence of the polar Kerr effect can be used as a sensitive probe of chemical ordering effects in binary intermetallic alloys. We demonstrate this effect in the Co50Pt50 alloy, which is known to have a L10 phase (critical temperature ≈852°C). Kerr spectra of the ordered and disordered phases of the Co50Pt50 alloy composition differ drastically from each other and the ordered phase shows an unprecedented, new peak at 2.2eV photon energy. The intensity of this new peak correlates with the degree of chemical ordering and the magnetic anisotropy in these films.