Dynamic spin correlations in stuffed spin ice Ho2+xTi2-xO7-δ

The magnetic correlations in stuffed spin ice Ho2+xTi2-xO7-delta have been characterized using quasielastic neutron scattering. At temperatures above 1 K, these correlations are short ranged in nature and dynamic on a picosecond to nanosecond time scale. As for the case of pure spin ice Ho2Ti2O7, one can identify, above the freezing temperature, a quantum relaxation regime which is enhanced as it persists to even higher temperatures, T similar to 30-40 K, than in the parent compound.