Perpendicular magnetic anisotropy and magneto-optical Kerr effect of vapor-deposited Co/Pt-layered structures

TLDR

Magnetic anisotropy in Co/Pt multilayers arises from interface contributions. Thin Co/Pt multilayers were fabricated by room‑temperature vapor deposition on glass or Si, and their magneto‑optical Kerr effect was characterized. The multilayers exhibit strong perpendicular magnetic anisotropy with 100 % remanence for Co layers < 4.5 Å, high oxidation resistance, and a modest Kerr rotation of –0.12° at 820 nm but a high figure of merit due to 70 % reflectivity, with the Kerr effect improving at shorter wavelengths, making them attractive for high‑density MO recording.

Abstract

We prepared by vapor deposition at room temperature thin (500 Å) Co/Pt multilayers or layered structures directly onto glass or Si substrates. They show a preferential magnetization perpendicular to the film plane for Co thicknesses below 12 Å and a 100% perpendicular remanence for Co thicknesses below 4.5 Å. The magnetic anisotropy can be explained by an interface contribution to the anisotropy. We also investigated the magneto-optical (MO) polar Kerr effect of these multilayers. Because of their excellent magnetic properties and their potentially high oxidation and corrosion resistance, these Co/Pt-layered structures are very promising candidates for MO recording. The Kerr rotation θk at λ=820 nm for a 35×(4.0 Å Co+12.7 Å Pt)-layered structure, which has 100% magnetic remanence, is modest (−0.12°), but the reflectivity R is high (70%), which results in a respectable figure of merit Rθ2k. Furthermore, the Kerr effect increases towards shorter wavelengths and thus favors future higher-density recording.