Dynamic Spin Correlations in a Pyrochlore Slab

ORAL

Abstract

We use neutron scattering to study the spin dynamics of Ba$_2$Sn$_2$ZnGa$_3$Cr$_7$O$_{22}$, an $S=3/2$ strongly frustrated, disorder free, quasi-two-dimensional spin system based on a kagom\'{e} sandwich. Low temperature spin freezing, with timescale dependent onset and magnitude, is observed. Relaxation rate distribution displays $\omega/T$ scaling, characteristic of quantum critical regime, and anomalously broadens below 11 K. Wavevector dependence of the excitation spectrum supports the notion that the dynamics is driven by the interaction of spin simplexes, which carry no dipole moment.

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Authors

  • Goran Gasparovic

    NIST and University of Maryland

  • S.-H. Lee

    University of Virginia

  • Collin Broholm

    Johns Hopkins University, Department of Physics and Astronomy, Johns Hopkins University, Baltimore MD 21218

  • R.J. Cava

    Princeton University, Princeton Univ., Department of Chemistry, Princeton University, Department of Chemistry, Princeton University, Princeton, NJ 08540, USA, Department of Chemistry, Princeton University, Princeton NJ 08544, USA