Topology, liquidity and glassiness in scandium-doped spin ice

We have studied the magnetic diffuse neutron scattering from a large single crystal of scandium-doped holmium titanate, and we find that the pinch points from classical spin ice, which reflect the emergent gauge field defining the Coulomb phase, remain intact when heavily doped. We now propose to determine the defect structures in scandium-doped holmium titanate using structural diffuse neutron scattering on SXD. These measurements will determine which oxygen sites become vacant, their relationship with the scandium ions, and the accompanying elastic displacements of surrounding ions. The results will be compared directly with our predictions using density functional theory. Our determination of the defect structure will enable us to calculate the effects on the single-ion magnetism, and to simulate the collective behaviour for this novel magnetic system.