1302.6353 (C. Fan et al.)

An irreversible magnetic-field dependence of low-temperature heat
transport of spin-ice compound Dy_2Ti_2O_7 in a [111] field    [PDF]

C. Fan, Z. Y. Zhao, H. D. Zhou, X. M. Wang, Q. J. Li, F. B. Zhang, X. Zhao, X. F. Sun

We study the low-temperature thermal conductivity (\kappa) of Dy_2Ti_2O_7 along and perpendicular to the (111) plane and under the magnetic field along the [111] direction. Besides the step-like decreases of \kappa at the field-induced transitions from the spin-ice state to the kagom\'e-ice state and then to the polarized state, an abnormal phenomenon is that the \kappa(H) isotherms show a clear irreversibility at very low temperatures upon sweeping magnetic field up and down. This phenomenon surprisingly has no correspondence with the well-known magnetization hysteresis. Possible origins for this irreversibility are discussed; in particular, a pinning effect of magnetic monopoles in spin ice compound by the weak disorders is proposed.

View original: http://arxiv.org/abs/1302.6353