We have studied the field-dependent ac magnetic susceptibility of single crystals of Dy2Ti2O7 spin ice along the [111] direction in the temperature range 1.8 K - 7 K. Our data reflect the onset of local spin ice order in the appearance of different field regimes. In particular, we observe a prominent feature at approximately 1.0 T that is a precursor of the low-temperature metamagnetic transition out of field-induced kagome ice, below which the kinetic constraints imposed by the ice rules manifest themselves in a substantial frequency-dependence of the susceptibility. Despite the relatively high temperatures, our results are consistent with a monopole picture, and they demonstrate that such a picture can give physical insight to the spin ice systems even outside the low-temperature, low-density limit where monopole excitations are well-defined quasiparticles.
@article{arxiv.1211.4280,
title = {High temperature onset of field-induced transitions in the spin-ice compound Dy2Ti2O7},
author = {M. J. Matthews and C. Castelnovo and R. Moessner and S. A. Grigera and D. Prabhakaran and P. Schiffer},
journal= {arXiv preprint arXiv:1211.4280},
year = {2015}
}