We studied in detail the low temperature/high magnetic field phases of URu2Si2 single crystals with specific heat, magnetocaloric effect, and magnetoresistance in magnetic fields up to 45 T. Data obtained down to 0.5 K, and extrapolated to T = 0, show a suppression of the hidden order phase at Ho(0) = 35.9 ± 0.35 T and the appearance of a new phase for magnetic fields in excess of H1(0) = 36.1 ± 0.35 T observed \textit{only} at temperatures lower than 6 K. In turn, complete suppression of this high field state is attained at a critical magnetic field H2(0) = 39.7 ± 0.35 T. No phase transitions are observed above 40 T. We discuss our results in the context of itinerant vs. localized \textit{f}-electron behavior and consider the implications for the hidden order phase.
@article{arxiv.cond-mat/0209500,
title = {High Field Studies of the Hidden Order Transition in URu$_2$Si$_2$},
author = {M. Jaime and K. H. Kim and G. Jorge and S. McCall and J. A Mydosh},
journal= {arXiv preprint arXiv:cond-mat/0209500},
year = {2009}
}