Unusual Behavior in The Magnetic Anisotropy of Ultra-Thin Co Sandwiches: The Role of Au Underlayers.

Abstract

ABSTRACTWe have used in situ polar Kerr effect measurements to study the magnetic anisotropy of X/Co/Y sandwich structures grown by MBE on Cu(111) buffers, where X and Y are variable thicknesses of Au. For fixed values of Y and in the case of an underlayer wedge, e.g. variable X value, we have found a sharp minimum in both coercive field and perpendicular anisotropy at ≈1 atomic layer of the Au underlayer. This anisotropy behavior is opposite to that of an Au overlayer deposited on a Co film, i.e. variable Y and fixed X.