Unconventional spin glass behavior in the cubic pyrochlore Mn2Sb2O7

The new pyrochlore Mn(2)Sb(2)O(7) has been synthesized via a low-temperature method to retain cubic Fd (3) over barm symmetry. The resulting material has an unconventional spin glass state at T(SG) similar to 41 K, in the absence of detectable site disorder or a structural phase transition. A peak in the DC susceptibility at T(SG), and a characteristic shift in the real part of the AC susceptibility was noted, but with a slightly more dynamic state than predicted through the typical Mydosh spin glass parameter of Delta T(SG)/[T(SG) log(omega)]. Time-dependent magnetization measurements show glassy behavior below 41 K. Elastic neutron scattering measurements on powder samples show significant magnetic diffuse scattering from the Mn spins beneath the transition, similar to the scattering observed in the spin liquid Tb(2)Ti(2)O(7). The dynamic character of Mn(2)Sb(2)O(7) is inferred to arise from the frustration inherent within the pyrochlore lattice.