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

A refined analysis of dispersive and absorptive contributions to the complex magnetic susceptibility yields detailed information on magnetic and structural properties of ultrathin films. The new ac modulated magnetic circular X-ray dichroism (MCXD) technique is described in detail. Experimental results from measurements at the L(2,3) edges of Ni and Co films are discussed in a more general framework including modulated magneto-optic Kerr effect and mutual inductance measurements of Gd films. A comparison of the experimentally determined small demagnetizing factors (N-II approximate to 10(-3)) of monolayers allows us to draw conclusions on the structure of the film. In addition, we show by element 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.