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Jamming Behavior of Domains in a Spiral Antiferromagnet

Seminar Group: 


Professor Sunil K. Sinha


Department of Physics
University of California, San Diego


Friday, May 17, 2013 - 4:00pm


ESB 1001


Professor Cyrus Safinya

Over the last few years, attempts have been made to unify many aspects of the freezing behavior of glasses, granular materials, gels, supercooled liquids, etc. into a general conceptual framework of what is called jamming behavior. This occurs when particles reach packing densities high enough that their motions become highly restricted. A general phase diagram has been proposed onto which various materials systems, e.g glasses or granular materials, can be mapped. In this talk I will show that at the ordering temperature the domains of an antiferromagnetic system, namely Dysprosium metal, behave very much also like a jammed system and their associated fluctuations exhibit behavior which exhibit some of the universal characteristics of jammed systems, such as non-exponential relaxation and Vogel-Fulcher type freezing. The dynamical fluctuations were studied using the technique of X-ray Photon Correlation Spectroscopy, i.e. by studying the fluctuations of the magnetic speckle pattern resulting from scattering of a coherent beam of x-ray photons tuned to a magnetic resonance of Dy.