Thermodynamic study of excitations in a three-dimensional spin liquid - art. no. 012412

In order to characterize thermal excitations in a frustrated spin liquid, w e have examined the magnetothermodynamics of a model geometrically frustrat ed magnet. Our data demonstrate a crossover in the nature of the spin excit ations between the spin-liquid phase and the high-temperature paramagnetic state. The temperature dependence of both the specific heat and magnetizati on in the spin-liquid phase can be fit within a simple model which assumes that the spin excitations have a gapped quadratic dispersion relation.