Exploring nanoscale magnetism in advanced materials with polarized X-rays

Nanoscale magnetism is of paramount scientific interest and high technological relevance. To control magnetization on a nanoscale, both external magnetic fields and spin polarized currents, which generate a spin torque onto the local spin configuration, are being used. Novel ideas of manipulating I he spins by electric fields or photons are emerging and benefit from advances in nano-preparation techniques of complex magnetic materials, such as multiferroics, ferromagnetic semiconductors, nanostructures, etc. Advanced analytical tools are needed for their characterization. Polarized soft X-rays using X-ray dichroism effects are used in a variety of spectroscopic and microscopic techniques capable of quantifying in an element, valence and site-sensitive way basic properties of ferro(i)- and antiferromagnetic systems, such as spin and orbital moments, nanoscale spin configurations and spin dynamics with sub-ns time resolution. Future X-ray sources, such as free electron lasers will provide an enormous increase in peak brilliance and open the fs time window to studies of magnetic material;. Thus fundamental magnetic time scales with nanometer spatial resolution can be addressed. This review provides an overview and future opportunities of analytical tools using polarized X-rays by selected examples of current research with advanced magnetic materials. (C) 2011 Elsevier B.V. All rights reserved.