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

BORZI, RODOLFO; GOMEZ ALBARRACIN, FLAVIA; H. D. ROSALES; ROSSINI, GERARDO; STEPPKE, A.; PRABHAKARAN, D.; MACKENZIE A.P. ; CABRA, DANIEL; GRIGERA, SANTIAGO

Otro; Artículos en referato; 2015

Nature Communications

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, DyTiO and HoTiO, 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.