A Faraday magneto-optical effect filter has been developed to convert linearly to elliptically polarized undulator radiation to provide magnetic circular dichroism (intensity) contrast from magnetic samples in an existing scanning transmission x-ray microscope. Strong magnetic contrast is observed across a 180degrees domain wall in a 33 nm thick demagnetized Fe film with in-plane magnetization, and clear structure is associated with the domain wall. By rotating the sample through large angles, magnetization components normal to the film are clearly observed and are associated with the domain wall structure, confirming that it is a cross-tie wall. Strengths and weaknesses of this approach compared to others are discussed.

We have observed circular and linear magnetic dichroisms in angle-resolved photoemission spectra of 50-monolayer Gd films grown on Y(0001) and 6-monolayer Fe-Ni alloy films grown on Cu(001). The 4/level of Gd and the Fe 3p level of the Fe-Ni alloy were measured. A different geometry was used for the magnetic circular dichroism than was used to measure the magnetic linear dichroism. The geometries were chosen so that the magnetic circular dichroism is predicted to be closely related to the magnetic linear dichroism for four-fold symmetric Fe-Ni/Cu(001) but not for three-fold symmetric Gd-Y(0001). Experimental results are presented.

Magnetic linear dichroism (MLD) in 4d–4f resonant and 4f nonresonant photoemission (PE) is studied from thin epitaxial gadolinium films. In an angle resolved and high-energy resolution mode, experiments were conducted with the electric-field vector of the incident light perpendicular to the sample magnetization. Our results show a significant difference in behavior of MLD in resonant PE as compared to that in nonresonant PE. Off-resonance, the MLD signal is dominated by a negative feature at the low binding energy side of the peak. Near the 4d–4f resonance maximum, the MLD displays a plus–minus shape, with a negative signal at the low binding energy side of the 4f peak and a positive signal at the high binding energy side. Analysis of MLD in 4d–4f resonant PE may provide insight into interactions of the 4d core hole with the 4f core level in the intermediate state.

Extending a single electron picture previously developed by Venus, it will be shown that a generalized prediction of the magnetic x-ray circular dichroism in the angle-resolved photoelectron spectroscopy of the Fe 3p can be obtained. This determination can be performed without resorting to time-consuming and difficult spectral simulations.

We have used the magnetic x-ray linear dichroism (MXLD) in angle-resolved photoemission and the magnetic x-ray circular dichroism (MXCD) in x-ray absorption to investigate the magnetic structure of nanoscale alloy films (thickness of about 1 nm) as a function of composition, with full elemental specificity. FeNi and FeCo films were grown using MBE techniques upon the surface of Cu(001). The MXLD measurements were made at the specromicroscopy facility of the third generation Advanced Light Source. The MXCD experiments were performed using the UC/National Laboratories PRT beamline at SSRL. The MXLD results will be directly compared to predictions of a theoretical model and magnetic moment determinations from MXCD-absorption. Crucial issues such as the Invar effect will be addressed.

Three closely related techniques, X-ray photoelectron spectroscopy, X-ray absorption spectroscopy, and X-ray fluorescence spectroscopy, have become widely accepted as important tools for the study of the chemical composition and electronic properties of surfaces, overlayers, and interfaces. There is now a major effort to push these spectroscopic techniques into a new realm of applications with very high spatial resolution, at and below 1 μm. This results in a new set of probes which can create images of chemical composition with great subtlety. The field is growing rapidly as high brightness sources of X-rays become available. The goals and methods used in electron spectromicroscopy and related X-ray microscopies are discussed, and recent applications of instruments developed in the last few years are used to illustrate the strengths of these new microscopes.

The radiation from the 5 cm period undulator at the Advanced Light Source (ALS) has been characterized using a transmission grating spectrometer. Spectral and angular distributions of radiation were measured for deflection parameter K values between 0.45 and 2.12 at low storage ring current (0.1–0.5 mA). From the calibration of the spectrometer, the absolute flux density of the undulator harmonics has been determined together with the spectral linewidth. The electron-beam emittance was determined by analyzing the angular distribution of the redshifted fundamental. Comparison has been made with radiation calculations based upon the measured magnetic-field data of the undulator. Including field errors, electron-beam emittance, and energy spread, good agreement is found between theoretically and experimentally determined harmonic widths and peak brightness.