Hartmann characterization of the PEEM-3 aberration-corrected X-ray photoemission electron microscope

Abstract

Aberration correction by an electron mirror dramatically improves the spatial resolution and transmission of photoemission electron microscopes. We will review the performance of the recently installed aberration corrector of the X-ray Photoemission Electron Microscope PEEM-3 and show a large improvement in the efficiency of the electron optics. Hartmann testing is introduced as a quantitative method to measure the geometrical aberrations of a cathode lens electron microscope. We find that aberration correction leads to an order of magnitude reduction of the spherical aberrations, suggesting that a spatial resolution of below 100 nm is possible at 100% transmission of the optics when using x-rays. We demonstrate this improved performance by imaging test patterns employing element and magnetic contrast.

Spatial and Temporal Correlations of XY Macro Spins

“…While this exposure time is sufficient for probing ensembles with a ≲ 155 nm at 390 K, spin fluctuations in lattices with a ≳ 160 nm exceed the temporal resolution limit of 2.5 s, leading to apparently uncorrelated system. We did not apply aberration correction, demonstrated to enhance spatial resolution and contrast levels, 43 due to yet unknown long-term stability. In particular, the transition may occur abruptly (<4 s, equal to half the acquisition time) or slowly, similar to domain wall creeping, over tens of minutes.…”