Article abstract


Nature Physics 3, 566 - 572 (2007)
Published online: 10 June 2007 | doi:10.1038/nphys632

Subject Categories: Condensed-matter physics | Statistical physics, thermodynamics and nonlinear dynamics

Pinch points and Kasteleyn transitions in kagome ice

T. Fennell1,2, S. T. Bramwell1,3, D. F. McMorrow1,2,4, P. Manuel4 & A. R. Wildes5


Complex disordered states—from liquids and glasses to exotic quantum matter—are ubiquitous in nature. Their key properties include finite entropy, power-law correlations and emergent organizing principles. In spin ice, spin correlations are determined by the 'ice rules' organizing principle that stabilizes a magnetic state with the same zero-point entropy as water ice. The entropy can be manipulated with great precision by an applied magnetic field: when directed along the three-fold crystallographic axis, the field produces a state of finite entropy, known as kagome ice. Here, we investigate the spin-ice material Ho2Ti2O7 by tilting the magnetic field slightly away from that axis. We thus realize a classic statistical system named after Kasteleyn, in which the entropy of a critical phase can be continuously tuned. Our neutron scattering experiments reveal how this process occurs at a microscopic level.

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  1. London Centre for Nanotechnology, 17-19 Gordon Street, London WC1H 0AJ, UK
  2. Department of Physics, University College London, Gower Street, London WC1E 6BT, UK
  3. Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, UK
  4. ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot OX11 0QX, UK
  5. Institut Laue Langevin, 6, rue Jules Horowitz BP156, 38042 Grenoble Cedex 9, France

Correspondence to: T. Fennell1,2 e-mail: t.fennell@ucl.ac.uk


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