Jungiusstr. 11, Hörsaal AP
SFB 668 - Kolloquium
Prof. Dr. Stefan Eisebitt (TU Berlin):
Watching Nanomagnets Switch: Probing Magnetism by Coherent X-Ray Scattering and Holography
Our most advanced x-ray sources ? modern 3rd generation synchrotrons and Free Electron Lasers ? provide a coherent photon flux that allows performing interference experiments with x-rays. I will present an overview on how x-ray holography can be used to record high resolution images in general and will focus on examples in the area of nanomagnetism, where we study the structure-function relationship in prototypes for bit patterend magnetic data storage media.
The fundamental timescale for ultrafast optical manipulation of the magnetization is the femto- and picosecond second regime. On these timescales, energy and angular momentum are transferred between the electrons, spins and the lattice, but the details of the mechanism of ultrafast optical demagnetization are under debate. As Free Electron X-ray Lasers provide intense x-ray pulses with sub-100 femtosecond duration, they open a route for the study of ultrafast magnetic phenomena with simultaneous nanometer spatial resolution. I will present results from recent IR-pump X-probe experiments in the area of femtomagnetism performed at FLASH, Hamburg, and LCLS, Stanford.