The magnetic susceptibility of ${}^3\mathrm{He}$ nanoclusters embedded in a ${}^4\mathrm{He}$ matrix has been measured from 0.5 to 10 mK at pressures from 2.88 to 3.54 MPa. Even the lowest pressure clusters have a solid fraction in the region of the phase diagram where bulk solid is unstable. At 3.54 MPa, $\theta =-250\mathrm{}\mu \mathrm{K}$, equal to that of bulk ${}^3\mathrm{He}$ for $v=21.3\mathrm{}{\mathrm{cm}}^3/\mathrm{mole}$. For 2.88 MPa, $\theta =140\mathrm{}\mu \mathrm{K}$, indicating a ferromagnetic tendency, similar to 2D films at some coverages. At intermediate pressures, $\chi$ has a peak near 1.05 mK, but with no discontinuity. Magnetic ordering in nanoclusters appears to be different than the U2D2 phase of bulk ${}^3\mathrm{He}$.

• Received 28 September 2000

DOI:https://doi.org/10.1103/PhysRevLett.86.2365