Magnetic X-ray circular dichroism on in situ grown 3d magnetic thin films on surfaces

Epitaxic thin and ultrathin films on surfaces allow crystallographic phases that do not occur naturally in the bulk to be stabilized. They also offer new possibilities for an improved understanding of soft X-ray photoabsorpti on in magnetic systems. Data collected using the Elliptically Polarizing Un dulator at BL 5.2 of the Stanford Synchrotron Radiation Laboratory are pres ented herein. Fe, Co and Ni films were prepared on Cu(100) surfaces. L-2,L- 3-edge spectra were recorded with circular and linear light. Fresnel diffra ctometry was used to quantify the degree of transverse beam coherence. A qu antitative analysis of the spectral features indicates a correlation of the spectral intensities and the transverse beam coherence. Resonant reflectiv ity spectra for Co ultrathin films that exhibit strong dichroism are presen ted. The reflectivity data indicate that interference effects of the reflec ted beams at the two interfaces are of importance, even for ultrathin films .