We report on the study of unusual spin glass properties in the geometrically frustrated pyrochlore ${\mathrm{Tb}}_2{\mathrm{Mo}}_2{\mathrm{O}}_7$, $T_g\simeq 24\mathrm{K}$. The analysis of the nonlinear part of dc and complex susceptibilities, near the glass transition regime, suggests the existence of a statistical distribution of relaxation times in short-range ordered ferromagnetic clusters. In addition, the magnetic spins are not sufficiently frozen below the glass transition temperature, which is apparently responsible for the nonequilibrium scaling behavior of the static critical exponents of nonlinear susceptibilities. Our report is expected to shed new light in understanding the freezing properties of frustrated pyrochlores with short-range ferromagnetic interactions.

• Received 23 July 2012

DOI:https://doi.org/10.1103/PhysRevLett.109.247201