Speaker: Yimei Zhu, Brookhaven
Date & Time: May 10, 2006 - 4:30pm
Location: Physics Lecture Hall
Revealing Nano-Scale Electronic and Magnetic Structure with Fast Electrons
Physics and Astronomy
Yimei Zhu, Brookhaven
4:30pm, Physics Lecture Hall
A challenge in solid state physics and materials science is to accurately measure electrostatic and magnetic potentials in crystals at nonometer scale. Facing such a challenge we developed a novel quantitative electron diffraction/imaging technique that is very sensitive to charge distribution in solid and can be used to test Density Functional Theory calculations. We present our recent work on the measurement of valence electron distribution and charge transfer in MgB2 superconductor and dielectric CaCu3Ti4O12. We also report our progress towards quantitative high-resolution phase microscopy including electron holography and non-interferometric phase retrieval methods to reveal magnetic structure information. Dynamic behavior of domains and their induction distribution during magnetization process and the reversal mechanism of patterned magnetic elements will be presented. New results on spin and electron interaction in manganites (La/SrMnO3) with antiferro- and ferro-magnetic multilayered structures will be discussed.
Work supported by Materials Science Division, Basic Energy Science, DOE under contract No.DE-AC02-98CH1-886.