| Simultaneous measurements of pressure, spin-lattice relaxation times (T1), spin-spin relaxation times (T 2), and magnetic susceptibility (χ) were made in 3He nanoclusters embedded in an hcp 4He matrix, following phase separation of the mixture.; Based on the pressure changes and magnetic susceptibility, three different types of behavior were identified, for which the clusters either remained all solid at the lowest temperature, underwent partial melting upon further cooling after phase separation or separated with liquid already present. Magnetic measurements were extended from 0.5 mK to above 10 mK for these three different pressure ranges from 2.88 to 3.54 MPa.; In the temperature range of the measurements, where pure bulk 3He would be entirely liquid, the magnetic behavior of the clusters for P ≤ 3.35 MPa indicated 3He solid fraction of about 77, 54, 23, and 19% respectively. The magnetic susceptibility χ of the 3.35-MPa sample followed a Curie law to 0.5 mK with &thetas; w = −5 ± 5 μK. For the 3.06- and 2.96-MPa samples, a kink in χ was observed at 1.1 mK, which is approximately the magnetic ordering temperature TN that would be expected for pure bulk 3He if it existed at this pressure. However, χ was almost constant down to 0.5 mK, with no drop at 1.1 mK, and a frequency shift of ≈10 ± 10 Hz, below 1.1 mK. Thus if there was magnetic ordering it appears to be quite different than for bulk 3He. For the 2.88-MPa sample, χ followed a Curie-Weiss law with a Weiss &thetas; = 140 μK, indicative of a ferromagnetic tendency, which is similar to that seen in 2D films.; Several spin-lattice relaxation times T1 were measured for each sample to estimate the necessary time interval between pulses. Anomalously short Zeeman-exchange-lattice T 1's were observed that may indicate distortion of the cluster at the interface with the 4He.; Spin-spin relaxation times T2 were measured in several samples in order to look for possible changes in the spin-spin interactions. No perceptible change was observed in measurements above and below 1.1 mK. |
