OSCILLATION OF MAGNETOOPTICAL KERR-EFFECT IN CO ULTRA-THIN FILMS

The thickness dependence of magneto-optical (MO) properties are measur ed in wedge-shaped Co films deposited on Au seed layers by the MBE met hod. It is found that Co ultra-thin film on fcc-Au(100) crystallizes i n bcc structure below the thickness of 6-10 Angstrom and changes from bcc to hcp structures from the RHEED observation. In 3.0-4.7 eV, new M O Kerr rotation (phi(K)) and Kerr ellipticity (eta(K)) peaks appear in Co(100) wedge sample and its shifts towards the higher energy side wi th increasing Co layer thickness. An oscillation of phi(K) and eta(K) as a function of Co thickness was also clearly observed. Such kinds of oscillatory behavior are unclear in hcp-Co(0001) wedges samples.