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

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

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.