SOFT-X-RAY CIRCULAR POLARIZER USING MAGNETIC CIRCULAR-DICHROISM AT THE FE L-3 LINE

Linearly polarized soft x-rays are converted to elliptical polarizatio n at the Fe L-3 line (707 eV) using magnetic circular dichroism (MCD) on transmission through thin Fe films. A linear polarizer measured the transmitted polarization at different incidence angles to vary as exp ected from a model for in-plane magnetization, and also to exhibit a w eak MCD effect at normal incidence interpreted to originate from perpe ndicular interface anisotropy. An MCD signal from a downstream Fe film was produced by switching the helicity of x-rays transmitted through an upstream circular polarizer. Practical considerations for optimizin g the production of circular polarization are discussed, and synchrotr on radiation applications using these circular polarizing filters are suggested.