Refrustration and competing orders in the prototypical Dy sub(2)Ti sub(2)O sub(7) spin ice material

Spin ices, frustrated magnetic materials analogous to common water ice, have emerged over the past 15 years as exemplars of high frustration in three dimensions. Recent experimental developments aimed at interrogating anew the low-temperature properties of these systems, in particular whether the predicted transition to long-range order occurs, behoove researchers to scrutinize our current dipolar spin ice model description of these materials. In this work, we do so by combining extensive Monte Carlo simulations and mean-field theory calculations to analyze data from previous magnetization, diffuse neutron scattering, and specific-heat measurements on the paradigmatic D[sub y[sub 2]], Ti[sub 2] O[sub 7] spin ice material. We show that among the four most likely causes for the observed upturn of the specific heat at low temperature, only the last appears to be reasonably able to explain the calorimetric data.