Strongly Polarized LiquidHe3: Experimental Access to the Melting Curve

By rapid decompression of 55% polarized solid ${}_{}{}^3{}_{}{}^{}\mathrm{He}$, we have measured a depression of the liquid-solid melting curve as large as 1 bar at 100 mK. It is found that the lowering $\Delta P$ depends on the global magnetization $m$. We explain this by a "dendritic melting" which ensures the homogeneity of the magnetization in each phase. $\Delta P$ has the expected $m^2$ dependence for small $m$. However, the slope $\frac{d\Delta P}{d{m}^2}$ is three times the expected value. A possible explanation is a rotation of the magnetization on melting.