Magnetic Susceptibility of 3He nano-Clusters

Using pulsed NMR, we have measured the magnetic susceptibility versus temperature of ³ He nano-clusters embedded in a matrix of ⁴ He, following phase separation of the mixture. Measurements were made in the temperature range from 2 mK to 35 mK at three different pressures, 3.647 MPa, 3.410 MPa and 3.075 MPa, for which the samples remain all solid, undergo partial melting, or are separated as a liquid, respectively. For 3.410 MPa, for which partial melting occurs near 15 mK, measurements up to 35 mK suggest a positive Weiss , which would indicate a ferromagnetic tendency.