Magneto-optical transition due to a formation of quantum well states in magnetic ultra-thin films and multilayers

Abstract

New magneto-optical (MO) Kerr rotation (φK) and Kerr ellipticity (ηK) peaks appear in 2.4–5.0 eV in bcc-Fe(001) and Co(100) ultra-thin films grown on fcc-Au(001) surface and the shifts towards the higher energy side with increasing Fe (Co) layer thickness are found. Oscillations of φK and ηK as a function of Fe or Co thickness were clearly observed by using a wedge-shaped Fe or Co samples. These types of behavior are, principally, well explained by a concept of quantum well states of Δ1 band in the bcc-Fe (or Co) ultra-thin films. Such oscillatory behavior is unclear in Fe(110), Fe(211) and hcp-Co(0001) wedged samples.