Monopole ordered phases in dipolar and nearest-neighbors Ising pyrochlore: From spin ice to the all-in?all-out antiferromagnet

P. C. GURUCIAGA; S. A. GRIGERA; R. A. BORZI

PHYSICAL REVIEW B - CONDENSED MATTER AND MATERIALS PHYSICS

American Physical Society

Lugar: New York; Año: 2014 vol. 90 p. 844231 - 844238

0163-1829

We study Ising pyrochlores by means of Monte Carlo simulations. We cover a set of exchange constantsranging from the frustrated ferromagnetic case (spin-ice) to the fully-ordered ?all-in?all-out? antiferromagnetin the dipolar model, reinterpreting the results?as in an ionic system?in terms of a temperature vs magneticcharge density phase diagram. In spite of its spin nature and the presence of both double and single nonconservedmagnetic charges, the dipolar model gives place to a phase diagram which is quite comparable with thosepreviously obtained for on-lattice systems of electric charges, and on spin ice models with a conserved number ofsingle magnetic charges. The contrast between these systems, to which we add results from the nearest-neighborsmodel, put forward other features of our phase diagram?notably, a monopole fluid with charge order at highmonopole densities that persists up to arbitrarily high temperatures?that can only be explained taking intoaccount construction constraints forced by the underlying spin degrees of freedom.