High Magnetic Field Studies of the Hidden Order Transition in ${\mathrm{U}\mathrm{R}\mathrm{u}}_{2}{\mathrm{S}\mathrm{i}}_{2}$

High Magnetic Field Studies of the Hidden Order Transition in ${U R u}_{2} {S i}_{2}$

M. Jaime, K. H. Kim, G. Jorge, S. McCall, and J. A. Mydosh

Phys. Rev. Lett. 89, 287201 – Published 26 December 2002

Abstract

We studied in detail the low temperature/high magnetic field phases of ${U R u}_{2} {S i}_{2}$ 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 $H_{0} (0) = 35.9 \pm 0.35 T$ and the appearance of a new phase for magnetic fields in excess of $H_{1} (0) = 36.1 \pm 0.35 T$ observed only at temperatures lower than 6 K. In turn, complete suppression of this high field state is attained at a critical magnetic field $H_{2} (0) = 39.7 \pm 0.35 T$ . No phase transitions are observed above 40 T. We discuss our results in the context of itinerant versus localized $f$ electrons.