1210.1242 (K. Fritsch et al.)

Antiferromagnetic Spin Ice Correlations at (1/2,1/2,1/2) in the Ground
State of the Pyrochlore Magnet Tb2Ti2O7    [PDF]

K. Fritsch, K. A. Ross, Y. Qiu, J. R. D. Copley, T. Guidi, R. I. Bewley, H. A. Dabkowska, B. D. Gaulin

We present high resolution single crystal time-of-flight neutron scattering measurements on the candidate quantum spin liquid pyrochlore Tb2Ti2O7 at low temperature and in a magnetic field. At ~70 mK and in zero field, Tb2Ti2O7 reveals diffuse magnetic elastic scattering at (1/2,1/2,1/2) positions in reciprocal space, consistent with short-range correlated regions based on a two-in two-out spin ice configuration on a doubled conventional unit cell. This elastic scattering is separated from very low energy magnetic inelastic scattering by an energy gap of 0.05 meV, which is clearly resolved here. The elastic signal disappears under the application of small magnetic fields and upon elevating temperature. Pinch-point-like elastic diffuse scattering is observed near (1,1,1) and (0,0,2) in zero field at ~70 mK, in agreement with Fennell et al. [1], supporting the quantum spin ice interpretation of Tb2Ti2O7.

View original: http://arxiv.org/abs/1210.1242