Soft X-ray Circular Reflectivity from Ferromagnetic Transition-Metal Films Near the Brewster's Angle: Theoretical and Numerical X-ray Resonant Magnetic Scattering Study

TL;DR

This study reveals a colossal difference in soft x-ray reflectivity between left- and right-handed circular polarization modes near Brewster's angle in ferromagnetic transition-metal films, due to destructive interference effects.

Contribution

It introduces a theoretical and numerical analysis of a novel polarization-dependent reflectivity phenomenon in ferromagnetic films at the Brewster's angle, highlighting a new interference-based mechanism.

Findings

Colossal reflectivity difference between LCP and RCP modes near Brewster's angle.

Reflectivity can be tuned from RCP to LCP by changing incidence angle.

The effect is due to destructive interference of scattered photons from charge and spin.

Abstract

We first report a novel phenomenon that manifests itself in a colossal difference in soft x-ray reflectivity from ferromagnetic transition-metal films between the left- and right-handed circular polarization (LCP and RCP) modes at a resonance near normal Brewster's angle. Theoretical and numerical studies of sft x-ray resonant magnetic scattering using the circular-polarization-mode basis reveal that this effect arises from a totally destructive interference of photons scattered individually from chargem orbital, and spin degrees of freedom in magnetized thin films that selectively occurs only for one helicity of the opposite circular modes when the required criteria are fulfilled. Across the normal Brewster's angle. the polarization state of scattered soft x-ray is continuously variable from the RCP to the LCP mode (or vice versa) through the linear s polarization mode by changing the incidence angle of linear p-polarized x rays at the resonance.