Observation of a liquid-gas-type transition in the pyrochlore spin ice compound Dy2Ti2O7 in a magnetic field -: art. no. 207205

Low temperature magnetization measurements on the pyrochlore spin ice compound Dy2Ti2O7 reveal that the ice-rule breaking spin flip, appearing at Hsimilar to0.9 T applied parallel to the [111] direction, turns into a novel first-order transition for T<0.36 K which is most probably of a liquid-gas type. T-linear variation of the critical field observed down to 0.03 K suggests the unusual situation that the entropy release across the transition remains finite [similar to0.5 (J/K).mol-Dy] as T-->0, in accordance with a breaking of the macroscopic degeneracy in the intermediate "kagome ice" state.