Enhanced magnetic dichroism in darkfield UV photoemission electron microscopy

TL;DR

This paper introduces darkfield UV PEEM to significantly enhance magnetic circular dichroism contrast, enabling more efficient and faster magnetic imaging at the nanoscale, especially for Fe(001).

Contribution

The study presents a novel darkfield PEEM technique that amplifies MCD contrast in UV photoemission, overcoming previous limitations of small dichroism effects.

Findings

Order-of-magnitude enhancement of MCD contrast for Fe(001)

Potential for femtosecond timescale MCD imaging with lasers

Quantitative benchmarking against relativistic calculations

Abstract

Photoemission electron microscopy (PEEM) has evolved into an indispensable tool for structural and magnetic characterization of surfaces at the nanometer scale. In strong contrast to synchrotron-radiation-based X-ray PEEM as a leading method for element-specific magnetic properties via magnetic circular dichroism (MCD), laboratory ultraviolet (UV) PEEM has seen limited application with much smaller dichroism effects for in-plane magnetization. Here we introduce darkfield PEEM as a novel approach to enhance MCD contrast in threshold photoemission, enabling efficient MCD imaging with significantly enhanced contrast by an order-of-magnitude for Fe(001). This advancement paves the way for MCD imaging on femtosecond timescales using modern lasers. The experimental results will be quantitatively benchmarked against advanced relativistic photoemission calculations.