Critical phenomena in a highly constrained classical spin system: Neel ordering from the Coulomb phase

T. S. Pickles; T. E. Saunders; J. T. Chalker

doi:10.1209/0295-5075/84/36002

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arXiv · 0708.3791

Critical phenomena in a highly constrained classical spin system: Neel ordering from the Coulomb phase

T. S. Pickles·T. E. Saunders·J. T. Chalker

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Abstract

Many classical, geometrically frustrated antiferromagnets have macroscopically degenerate ground states. In a class of three-dimensional systems, the set of degenerate ground states has power-law correlations and is an example of a Coulomb phase. We investigate Neel ordering from such a Coulomb phase, induced by weak additional interactions that lift the degeneracy. We show that the critical point belongs to a universality class that is different from the one for the equivalent transition out of the paramagnetic phase, and that it is characterised by effective long-range interactions; alternatively, ordering may be discontinuous. We suggest that a transition of this type may be realised by applying uniaxial stress to a pyrochlore antiferromagnet.

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T. S. Pickles, T. E. Saunders, J. T. Chalker. 2007-08-28. Critical phenomena in a highly constrained classical spin system: Neel ordering from the Coulomb phase. https://doi.org/10.1209/0295-5075/84/36002

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