High Contrast Magnetic and Nonmagnetic Sample Current Microscopy for Bulk and Transparent Samples Using Soft X-Rays

Abstract

The soft X-ray energy range provides important detection capabilities for a wide range of material systems, e.g., the K-edge behavior of biological materials or magnetic contrast imaging at the L2,3- and M4,5-edges, respectively, using the X-ray magnetic circular dichroism effect. The need for thinned samples due to the short penetration depth of soft X-rays is a limiting factor for microscopic imaging in transmission microscopy. In contrast, the more surface sensitive photoelectron emission microscopy allows the X-ray microscopic investigation of nontransparent bulk samples, but only small magnetic fields and very smooth surfaces are possible. As both high magnetic fields as well as bulk samples are important for magnetic imaging, we present total electron yield (TEY) microscopy results using the total sample current detection performed at the new ultra high vacuum scanning microscope "MAXYMUS" at HZB/BESSY II. We compare synchronous measurements in TEY and transmission mode to demonstrate the capabilities of TEY microscopy. Pictures and spectra with high absorption contrast and three-dimensional-like edge enhancement are observed as known for scanning electron microscopy. This unveils details on smallest length scales of the surface morphology. Furthermore, surface sensitive in- and out-of-plane magnetic TEY measurements at nontransparent samples are shown.