Figure 1

The $B>30\mathrm{T}$ versus $T$ phase diagram of ${\mathrm{U}\mathrm{R}\mathrm{u}}_2{\mathrm{S}\mathrm{i}}_2$ combined with a color intensity plot of $\chi$ measured at many different temperatures. Square, triangle, and circle symbols mark $B_{\mathrm{M}}$ and transitions into and out of the HO and RHO hidden order (RHO) phases, respectively. The curved dotted lines depict the continuation of the phase boundaries revealed by specific heat and transport studies [4].Reuse & Permissions

Figure 2

(a) $M$ of ${\mathrm{U}\mathrm{R}\mathrm{u}}_2{\mathrm{S}\mathrm{i}}_2$ at several different temperatures for $B$ applied along the $c$ axis. (b) $\chi$ in the vicinity of $B_{\mathrm{M}}$ at several temperatures above the reentrant ordering temperature. (c) $\chi$ at $B_{\mathrm{M}}$ and at $B\approx 34\mathrm{T}$ as a function of $T$.Reuse & Permissions

Figure 3

(a)–(e) Schematics of the evolution of the total DOS in ${\mathrm{U}\mathrm{R}\mathrm{u}}_2{\mathrm{S}\mathrm{i}}_2$ with $B$ (as indicated) before (red lines) and after (black lines) formation of the HO or RHO phases. Prior to ordering, mixing between conduction electron states and $f$-electron states gives rise to a large “Abrikosov-Suhl resonance”-like feature [11]. (f) A plot of the transition temperature squared $T_0^2$ versus the magnetic field squared $B^2$ taken from specific heat and transport data in Ref. 4.Reuse & Permissions