May 2006 Archives

The traditional tools of nanotechnology - the atomic force microscope and the scanning tunneling microscope - enable scientists to see atoms, but not their response to events, which at that scale occur in the order of nano seconds or shorter. Professor P. Evans (Univ of Wisconsin-Madison) and his colleagues recently succeeded in visualizing domain wall motion during polarization switching of a Pb(Zr,Ti)O₃ capacitor using time-resolved x-ray microdiffraction. The work was done using Argonne National Laboratory's Advanced Photon Source, a synchrotron light source capable of generating very tightly focused beams of X-rays. The X-rays are delivered to the sample in fast pulses over an area no larger than hundreds of nm. For more information, see the paper, "Nanosecond Domain Wall Dynamics in Ferroelectric Pb(Zr,Ti)O₃ Thin Films", A. Grigoriev et al., Phys. Rev. Lett. 96, 187601 (2006).

Located on the Plateau de Saclay, in the Essonne department, SOLEIL is the second 3^rd-generation synchrotron to be built in France - the first one, the ESRF in Grenoble, was a European project. Very recently, SOLEIL accelerated and injected electrons for the first time in its storage ring. On May 14, the electrons turned at a speed close to that of light in the 354 m circumference storage ring. The first 2.75 GeV beam injection from the Booster started around noon on May 13. After 12 hours spent on measurements and adjustments, the electrons made a full turn, and the first photon beams were observed. For more information, visit http://www.synchrotron-soleil.fr/anglais/index.html

It is well known that a piece of metal deforms in an irreversible or plastic manner when it is bent. This property is important from the standpoint of the feasibility of forming various types of metallic products as well as toughness as a structural material. Scientists from Riso National Laboratory, Denmark recently tried taking "snapshots" with hard X-rays. They observed some extremely interesting phenomena, i.e., the emergence and disappearance of the dislocation structure, which takes place during deformation. For more information, see the paper, "Formation and Subdivision of Deformation Structures During Plastic Deformation", B. Jakobsen et al., Science 312, 889 (2006).