We report low temperature specific heat and muon spin relaxation/rotation (μSR) measurements on both polycrystalline and single crystal samples of the pyrochlore magnet Yb2Ti2O7. This system is believed to possess a spin Hamiltonian supporting a Quantum Spin Ice (QSI) ground state and to display sample variation in its low temperature heat capacity. Our two samples exhibit extremes of this sample variation, yet our μSR measurements indicate a similar disordered low temperature state down to 16 mK in both. We report little temperature dependence to the spin relaxation and no evidence for ferromagnetic order, in contrast to recent reports by Chang \emph{et al.} (Nat. Comm. {\bf 3}, 992 (2012)). Transverse field (TF) μSR measurements show changes in the temperature dependence of the muon Knight shift which coincide with heat capacity anomalies. We are therefore led to propose that Yb2Ti2O7 enters a hidden order ground state below Tc∼265 mK where the nature of the ordered state is unknown but distinct from simple long range order.
@article{arxiv.1303.3850,
title = {Unconventional Magnetic Ground State in Yb$_2$Ti$_2$O$_7$},
author = {R. M. D'Ortenzio and H. A. Dabkowska and S. R. Dunsiger and B. D. Gaulin and M. J. P. Gingras and T. Goko and J. B. Kycia and L. Liu and T. Medina and T. J. Munsie and D. Pomaranksi and K. A. Ross and Y. J. Uemura and T. J. Williams and G. M. Luke},
journal= {arXiv preprint arXiv:1303.3850},
year = {2014}
}
Comments
Accepted for publication in Phys. Rev. B. 5 pages, 4 figures