Dr. Gergory Denbeaux
College of Nanoscale Science and Engineering, UAlbany
X-ray Microscopy – A Tool for High Resolution Imaging
There is an increasing need for high resolution techniques for imaging at the nanometer scale. Conventional techniques, such as visible light microscopy, have inherent limitations since it is challenging to images features smaller than the wavelength of the light used by the microscope. Electron microscopes avoid this wavelength limitation, but are not suited for all samples due to their need for vacuum and inability to penetrate thick samples. For applications where specialized contrast mechanisms are required (like with magnetic samples) or when wet samples are required for biological imaging, x-rays can provide useful imaging capabilities. By using a transmission x-ray microscope with precision zone plate optics, imaging can be achieved with a demonstrated spatial resolution finer than 25 nm. Image contrast can be obtained with x-ray magnetic circular dichroism, allowing direct imaging of the element-specific orientation of the magnetization within samples. The ability to magnetically characterize samples with 25 nm resolution gives a deeper understanding of magnetic properties and paves the way for future progress in such technically relevant fields as high-density magnetic storage in hard disk drives. Recent experiments have exploited the element-specific magnetic contrast to measure the magnetization of each layer in a bi-layer system, which is the likely design for future perpendicular magnetic recording devices. While the current emphasis of experimentation with the microscope is on understanding magnetic properties on the nanometer scale, a brief synopsis will also be given of other recent high resolution imaging studies of electromigration in passivated interconnects, high-resolution tomography of biological samples, and mask inspection for extreme ultraviolet lithography.
No charge for paid-up CDMMS members, $5 for non-members.
No RSVP necessary
For directions, go to http://www.igc.com/superpower/contact/directions/sp_directions.htm