Substantial Nuclear Ordering in SolidHe3

Evidence for a substantial nuclear ordering in solid bcc ${\mathrm{He}}^3$ at melting pressure has been inferred from solid entropies $s_S$ deduced from measurements of the slope of the melting curve for a liquid-solid mixture cooled by adiabatic compression. At 3.4 mK we find experimentally that $\frac{s_S}{R}=0.83\mathrm{}\ln 2$. It is likely that much lower temperatures and solid entropies are obtained during parts of the experiments. The possibility for bulk nuclear polarization is also discussed.