Intermediate magnetisation state, distortions and competing orders in DyTiO and HoTiO7

R. BORZI; F. GÓMEZ ALBARRACÍN; H.D. ROSALES; G. L. ROSSINI; A. STEPKE; D. PRABHAKARAN; A. P. MACKENZIE; D. C. CABRA; S. GRIGERA

NATURE COMMUNICATIONS

Nature Publishing Group

Año: 2016 vol. 7

2041-1723

Among the frustrated magnetic materials, spin-icestands out as a particularly interesting system. Residualentropy, freezing and glassiness, Kasteleyn transitions andfractionalisation of excitations in three dimensions allstem from a simple classical Hamiltonian. But is the usualspin-ice Hamiltonian a correct description of theexperimental systems? Here we address this issue bymeasuring magnetic susceptibility in the two most studiedspin-ice compounds, Dy2Ti2O7 and Ho2Ti2O7 , using a vectormagnet. Using these results, and guided by a theoreticalanalysis of possible distortions to the pyrochlore lattice,we construct an effective Hamiltonian and explore it usingMonte Carlo simulations. We show how this Hamiltonianreproduces the experimental results, including theformation of a phase of intermediate polarisation, andgives important information about the possible groundstate of real spin-ice systems. Our work suggests anunusual situation in which distortions might contribute tothe preservation rather than relief of the effects offrustration.