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Jamming Behavior of Domains in a Spiral Antiferromagnet

Seminar Group: 

Speaker: 

Professor Sunil K. Sinha

Address: 

Department of Physics
University of California, San Diego

Date: 

Friday, May 17, 2013 - 4:00pm

Location: 

ESB 1001

Host: 

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.