|X-Ray Diffraction Microscopy of Magnetic Structures|
Scientists working at ALS Beamline 18.104.22.168 have demonstrated a new x-ray technique for producing short-exposure nanoscale images of the magnetic structure of materials. The new method combines aspects of coherent x-ray diffraction, which can determine 3-D charge distributions, and resonant magnetic scattering, which is sensitive to magnetic structures.
Physicists have used coherent x-ray diffraction to measure the electron density of complicated molecules. The formula used to make these calculations contains terms that relate to the electron spin of magnetic atoms, but these terms are traditionally ignored since coherent x-ray diffraction has not been used to retrieve magnetic information. Using the full formula allows for the determination of not only the electron density, but also the magnetic spin distribution and its orientation.
After three years of trials and improvements, the research group, led by scientists from the Linac Coherent Light Source, succeeded in imaging magnetic domains in a cobalt alloy sample. This method can be used at any coherent light source, such as x-ray free-electron lasers, where ultra-short pulses would freeze-frame magnetic changes, offering the potential for imaging in unprecedented detail the structure and motion of boundaries between regions with different magnetic orientation.
Read the full ALS Science Highlight about this work: Lensless Imaging of Magnetic Nanostructures
Work performed on ALS Beamline 22.214.171.124
Citation: J.J. Turner et al., “X-Ray Diffraction Microscopy of Magnetic Structures,” Phys. Rev. Lett. 107, 033904 (2011).