APS March Meeting 2011
Volume 56, Number 1
Monday–Friday, March 21–25, 2011;
Dallas, Texas
Abstract: D18.00010 : Spin dynamics in the hyperkagome compound Gd$_{3}$Ga$_{5}$O$_{12}$
4:18 PM–4:54 PM
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Author:
We present the first neutron inelastic scattering results
on the magnetic state of the frustrated hyperkagome compound $\rm
Gd_3Ga_5O_{12}$ (GGG) at low temperatures and in applied magnetic
field.
Our neutron scattering studies reveal a remarkable range of
timescales. Short-range spatial correlations appear static within
the instrumental resolution (50~$\mu$eV).
Three distinct inelastic modes are found at 0.04(1), 0.12(2) an
0.58(3)~meV at 0.06~K. The application of a magnetic field up to
2.5~tesla reveals disparate behavior of the magnetic excitations.
In zero applied field, the lowest and highest energy excitations
show spatial dependencies indicative of dimerized short-range
antiferromagnetic correlations that survive to high
temperatures, comparable to the nearest neighbor exchange
interactions.
Our results suggest that the ground state of a three dimensional
hyperkagome compound differs distinctly from its frustrated
counterparts on a pyrochlore lattice and reveal a juxtaposition
of cooperative paramagnetism and strong dimerized coupling. These
results are surprising since GGG is often classified as a
strongly frustrated system with a manifold of connected states
for which one would expect a continuum of gapless excitations.
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In collaboration with: Pascale Deen, Institut Laue Langevin; G.
Balakrishnan, Department of Physics, University of Warwick; B.D.
Rainford, Department of Physics and Astronomy, Southampton
University; C. Ritter, Institut Laue-Langevin; L. Capogna,
Istituto Officina dei Materiali, IOM-CNR; H. Mutka and T.
Fennell, Institut Laue-Langevin.
To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2011.MAR.D18.10