Statics and dynamics of the highly correlated spin ice Ho 2 Ge 2 O 7

The pyrochlore Ho${}_{2}$Ge${}_{2}$O${}_{7}$ is a new highly correlated spin ice material. Physical property measurements, including x-ray diffraction, dc susceptibility, and ac susceptibility, confirm that it shares the distinctive characteristics of other known spin ices. Polarized neutron scattering measurements on a powder sample, combined with reverse Monte Carlo (RMC) refinements, give unique information about the spin ice state in Ho${}_{2}$Ge${}_{2}$O${}_{7}$. RMC refinements are used to fit the powder magnetic diffuse scattering and predict the single-crystal magnetic scattering of Ho${}_{2}$Ge${}_{2}$O${}_{7}$, demonstrating consistency with spin ice behavior.