The low temperature magnetic properties of pyrochlore compound Dy2Ti2O7 in magnetic fields applied along the [111] direction are reported. Below 1 K, a clear plateau has been observed in the magnetization process in the field range 2~9 kOe, followed by a sharp moment jump at around 10 kOe that corresponds to a breaking of the spin ice state. We found that the plateau state is disordered with the residual entropy of nearly half the value of the zero-field state, whose macroscopic degeneracy comes from a frustration of the spins on the kagome layers perpendicular to the magnetic field.
@article{arxiv.cond-mat/0207543,
title = {A new macroscopically degenerate ground state in the spin ice compound Dy2Ti2O7 under a magnetic field},
author = {Kazuyuki Matsuhira and Zenji Hiroi and Takashi Tayama and Seishi Takagi and Toshiro Sakakibara},
journal= {arXiv preprint arXiv:cond-mat/0207543},
year = {2009}
}