INFLUENCE OF A NONMAGNETIC UNDERLAYER ON THE MAGNETIC-ANISOTROPY OF ULTRA-THIN CO SANDWICHES

We have used in situ polar Kerr effect measurements to study the magne tic anisotropy of MBE-grown Cu/Au/Co/Au sandwich structures. We report ed earlier that the magnitude of the Au/Co/Au perpendicular anisotropy is strongly peaked at similar to 1 atomic layer Au overlayer coverage . We report here extensions of this work to investigate the influence on anisotropy of a confined ultra-thin non-magnetic underlayer placed at one of the Co interfaces. Sandwich structures were deposited in a s tepped-wedge geometry providing multiple underlayer thicknesses for ea ch sample. For the case of an underlayer wedge of Au, e.g. Cu/Au(x)/Co /Au, we find a sharp minimum in the perpendicular anisotropy at simila r to 1 atomic layer of Au. This anisotropy behavior is opposite to tha t of a Au overlayer deposited on a Co film.