Field-tuned order by disorder in frustrated ising magnets with antiferromagnetic interactions

GURUCIAGA, P.C.; TARZIA, M.; FERREYRA, M.V.; CUGLIANDOLO, L.F.; GRIGERA, S.A.; BORZI, R.A.

PHYSICAL REVIEW LETTERS

AMER PHYSICAL SOC

Año: 2016 vol. 117

0031-9007

We demonstrate the appearance of thermal order by disorder in Ising pyrochlores with staggered antiferromagnetic order frustrated by an applied magnetic field. We use a mean-field cluster variational method, a low-temperature expansion, and Monte Carlo simulations to characterize the order-by-disorder transition. By direct evaluation of the density of states, we quantitatively show how a symmetry-broken state is selected by thermal excitations. We discuss the relevance of our results to experiments in 2D and 3D samples and evaluate how anomalous finite-size effects could be exploited to detect this phenomenon experimentally in two-dimensional artificial systems, or in antiferromagnetic all-in-all-out pyrochlores like Nd2Hf2O7 or Nd2Zr2O7, for the first time.