Lawrence Berkeley National Laboratory

The exchange length and the precession frequency of the magnetization determine the fundamental length and time scales of a magnetic system: Nanometers and Picoseconds. X-ray spectro microscopy, which provides spectroscopic information on a nanometer scale, is uniquely suited for the microscopic study of the properties of complex magnetic systems because of its key strengths: Element specificity and quantitative magnetic sensitivity to ferro magnets and anti ferro magnets. Firstly I will introduce the X-ray PEEM technique and its application to multi-domain, layered systems, employing magnetic linear and circular dichroism. I will present domain images of anti ferro magnetic materials and will review implications to the old problem of exchange bias at the ferro magnet/anti ferro magnet interface. Subsequently, I will introduce a new approach to the investigation of nanoscale magnetization dynamics using x rays. The pulsed nature of synchrotron radiation facilitates 2-color pump-probe experiments with 50 ps time resolution. A fast heating, a current or a field pulse is first generated by a pulsed infrared laser and stimulates a magnetic response, which is then repetitively image dusing a synchrotron pulse at a fixed time delay. This stroboscopic method is similar to optical probe techniques, but offers superior spatial resolution and element specificity to only list a few advantages. I will show first results and will then discuss exciting applications for this new technique.