Speaker: Sujoy Roy, Lawrence Berkeley National Laboratory
Program Description
Understanding new states in condensed matter systems is a current research topic of interest due to both the unique physics and their potential in device applications. These phases have exotic properties, and in some cases can be moved coherently over macroscopic distances with very low currents. In this talk we will discuss x-ray photon correlation spectroscopy using resonantly tuned x-ray beam to study thermally induced domain fluctuation of a helical antiferromagnet near the ordering temperature. The fluctuations exhibit a behavior which is similar to some of the universal characteristics of jammed systems such as polymers, gels, etc. We will then discuss observation of skyrmions using resonant soft x-ray scattering in the helical system Cu2OSeO3 and demonstrate the unexpected existence of two distinct skyrmion sub-lattices. The skyrmion sublattices are rotated with respect to each other implying a long wavelength modulation of the lattice. Finally, we will discuss creation of x-ray vortex beam using an ordered array of magnetic monopole defects in an artificial spin ice structure.
Work is funded by U.S. DOE.
