Local X-ray Magnetic Circular Dichroism of Fe/Cu(111) using Synchrotron STM*

Synchrotron X-ray Scanning Tunneling Microscopy (SX-STM) combines two of the most powerful materials characterization methods; synchrotron X-ray and STM, and it has a great potential to revolutionize X-ray chemical imaging at the atomic limits. Here, we use SX-STM to study the x-ray magnetic circular dichroism (XMCD) on the Fe L2 and L3 edges of a thin iron film deposited on Cu (111) surface in room temperature. Polarization dependent x-ray absorption spectra have been obtained through a specially fabricated tip that captures photo-electrons. Unlike conventional spin-polarized STM, x-ray excitations provide magnetic contrast even with a non-magnetic tip. Intensity changes in the photo-excited current indicate chemical variations within a single magnetic Fe domain thereby opening up exciting opportunities to study local magnetic properties of materials using the SX-STM-XMCD method.