Publications (2)0 Total impact
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ABSTRACT: The rare earth pyrochlore material Gd2Ti2O7 is considered to be an ideal model frustrated Heisenberg antiferromagnet with additional dipolar interactions. For this system there are several untested theoretical predictions of the ground state ordering pattern. Here we establish the magnetic structure of isotopically enriched (160)Gd2Ti2O7, using powder neutron diffraction at a temperature of 50 mK. The magnetic structure at this temperature is a partially ordered, non-collinear antiferromagnetic structure, with propagation vector k= 1/2 1/2 1/2. It can be described as a set of "q=0" ordered kagome planes separated by zero interstitial moments. This magnetic structure agrees with theory only in part, leaving an interesting problem for future research. Comment: 4 pages, 2 figures
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S. Bramwell,
M. Harris,
B. den Hertog,
M. Gingras,
J. Gardner,
D. McMorrow,
A. Wildes,
A. Cornelius, J. Champion,
R. Melko,
T. Fennell
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ABSTRACT: The pyrochlore material Ho2Ti2O7 has been suggested to show "spin ice" behavior. We present neutron scattering and specific heat results that establish unambiguously that Ho2Ti2O7 exhibits spin ice correlations at low temperature. Diffuse magnetic neutron scattering is quite well described by a nearest neighbor spin ice model and very accurately described by a dipolar spin ice model. The heat capacity is well accounted for by the sum of a dipolar spin ice contribution and an expected nuclear spin contribution, known to exist in other Ho3+ salts. These results settle the question of the nature of the low temperature spin correlations in Ho2Ti2O7 for which contradictory claims have been made.
