AC SUSCEPTIBILITY MEASUREMENTS OF MAGNETIC MONOLAYERS - MCXD, MOKE, AND MUTUAL INDUCTANCE

A refined analysis of dispersive and absorptive contributions to the c omplex magnetic susceptibility yields detailed information on magnetic and structural properties of ultrathin films. The new ac modulated ma gnetic circular X-ray dichroism (MCXD) technique is described in detai l. Experimental results from measurements at the L(2,3) edges of Ni an d Co films are discussed in a more general framework including modulat ed magneto-optic Kerr effect and mutual inductance measurements of Gd films. A comparison of the experimentally determined small demagnetizi ng factors (N-II approximate to 10(-3)) of monolayers allows us to dra w conclusions on the structure of the film. In addition, we show by el ement specific ac MCXD susceptibility measurements that in a 1.3 ML Co /5.3 ML Ni bilayer the coupled films become ferromagnetic at the same Curie temperature.