AVS 62nd International Symposium & Exhibition
    Novel Trends in Synchrotron and FEL-Based Analysis Focus Topic Monday Sessions
       Session SA-MoM

Invited Paper SA-MoM8
Exploring All-optical Magnetic Switching with Resonant X-rays

Monday, October 19, 2015, 10:40 am, Room 112

Session: Imaging and Nanodiffraction (8:20-10:00 am) & Novel Insights in Correlated Materials, Organic Materials and 2D Solids (10:40 am -12:00 pm)
Presenter: Alexander Reid, SLAC National Accelerator Laboratory
Correspondent: Click to Email
The ability to write a magnetic `bit’, a stable magnetic domain, with a single sub-picosecond optical pulse is now known and demonstrated in magnetic materials from amorphous ferrimagnets, such as GdFeCo, to crystalline ferromagnets, such as FePt. However, understanding the underlying physics of this process remains a fundamental challenge in magnetism dynamics. The process of all-optical switching of magnetization begins with the absorption of the optical pulse by the magnetic material, this creates a highly non-equilibrium state. The evolution of this state is controlled by many factors, from fundamental coupling interactions to material heterogeneity. Resonant x-rays allow a powerful tool for exploring the evolution of this non-equilibrium state and beginning to answer questions about how and why reversed magnetic order can emerge deterministically. Powerful new x-ray sources, such and the Linac Coherent Light Source, produce femtosecond x-ray pulses with a high spatial coherence and brightness. Using such sources, and techniques such as x-ray circular magnetic dichroism, the transient elemental magnetism can be monitored during the switching process. Further, the intrinsically shorter wavelength of x-rays enables monitoring of the spatial aspects of the switching process down to length scales of a few nanometers. We detail recent measurement of the spatio-temporal dynamics of the switching process in the prototype materials GdFeCo and TbFeCo, which have led to new insights about the evolution of the optical magnetic switching process.