Spin-reorientation transition and magnetic phase diagrams of thin epitaxial Au(111)/Co films with W and Au overlayers

We present a study of the thickness- and temperature-driven spin-reorientat ion transition in thin epitaxial Au(111)/Co films grown on single-crystal s apphire Al2O3 (11 (2) over bar0) substrates. The transition as a function o f Co film thickness was investigated in situ at T=300 K by means of the mag neto-optical Kerr effect at Co wedge-shaped samples prior and after coverag e with W and An overlayers. The thermal-induced transition, in particular t he evolution and stability of in-plane and out-of-plane magnetization compo nents, was studied in the temperature range from 10 to 300 K by reflectivit y experiments with polarized neutrons and angular-dependent measurements wi th superconducting quantum interference device magnetometry. Magnetic phase diagrams, as determined by extended measurements on Au(111)/Co/Au and Au(1 11)/Co/W show that for the former films the perpendicular anisotropy is sta ble over a larger thickness region at low temperature.