Spin freezing in the geometrically frustrated pyrochlore antiferromagnet Tb2Mo2O7

Abstract

The magnetic metal ions in the cubic pyrochlore ${\mathrm{Tb}}_2$ ${\mathrm{Mo}}_2$ ${\mathrm{O}}_7$ form an infinite three-dimensional network of corner-sharing tetrahedra with a very high potential for frustration in the presence of antiferromagnetism. We have performed neutron scattering measurements which show short-range spatial correlations that develop continuously with decreasing temperature, while the characteristic time scale for the fluctuating moments decreases dramatically below ${\mathit{T}}_{\mathit{f}}$∼25 K. Therefore, this pure material, which possess frustration that is purely geometrical in origin, displays a spin-glass state at low temperatures.