Soft dipolar spin ice physics and the ordered phase of the frustrated Tb2Sn2O7 pyrochlore magnet

Paul A. McClarty; Pawel Stasiak; Michel J. P. Gingras

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arXiv · 1011.6346

Soft dipolar spin ice physics and the ordered phase of the frustrated Tb2Sn2O7 pyrochlore magnet

Paul A. McClarty·Pawel Stasiak·Michel J. P. Gingras

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Abstract

From a microscopic model for the pyrochlore antiferromagnet Tb2Sn2O7, including the crystal field Hamiltonian and interactions between the angular momenta, we compute an effective pseudospin-1/2 Hamiltonian Heff$ that incorporates perturbatively in the effective interactions the effect of excited crystal field levels. We obtain the semiclassical ground states of Heff and find a region of parameter space with a two-in/two-out spin ice configuration on each tetrahedron with ordering wavevector q=0 and with spins canted away from the local Ising axes as found in Tb2Sn2O7. This ground state can also be obtained from a dipolar spin ice model in which the Ising constraint is softened. Monte Carlo simulations on the latter model reveal a region of the phase diagram with spin ice-like freezing and another with a transition into Tb2Sn2O7-type long range order. We comment on the differences between Tb2Sn2O7 and the perplexing spin liquid Tb2Ti2O7.

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Paul A. McClarty, Pawel Stasiak, Michel J. P. Gingras. 2010-11-29. Soft dipolar spin ice physics and the ordered phase of the frustrated Tb2Sn2O7 pyrochlore magnet. https://arxiv.org/abs/1011.6346

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