Spectroscopy of Spin Fluctuations in Spin Ices*

In the past decade, the theoretical prediction of emergent magnetic charges in several lanthanide-pyrochlore magnetic insulators¹ has spawned renewed experimental interest in the study of these elusive particles, albeit in a condensed matter system. Thermodynamic and transport studies of of the spin ice of Dy₂Ti₂O₇ and Ho₂Ti₂O₇ are the focus of research. We report new studies of the spin fluctuation spectrum in these materials and analyze the data in the context of theories for thermally generated magnetic monopole pairs.
1. Castelnovo C., Moessner R., Sondhi S.L., Nature 451, 42 (2008)