R. Jochemsen

Comparison of some glass thermometers at low temperatures in a high magnetic field

We have compared the low‐frequency capacitance of glass thermometers of various shapes, made of very pure SiO2 doped with ≊1200 ppm OH−, in the temperature range of 4–100 mK in a magnetic field of 9 T. The construction of the electrodes, the way the contacts are made, and the connection of the leads or cables influence both the voltage and the field dependence of the capacitance and of the loss. We have been able to construct capacitive glass thermometers of which the capacitance is not shifted in a field of 9 T at temperatures down to 4 mK, within our temperature accuracy of ≊5%. This has been determined by comparison with a cerium magnesium nitrate (CMN) thermometer in a field‐free region, and by comparing ultrasound measurements versus the thermometer capacitance with and without a magnetic field.

The polarization dependence of the viscosity of liquid3He

We describe measurements on the viscosity of liquid3He as a function of its nuclear polarization between 80 and 350 mK. The viscosity was measured with a vibrating wire viscometer, and the polarization of the liquid was enhanced using the Castaing-Nozières effect. The polarization dependence of the viscosity can be written as η ∝ 1+αΔ2, with α=3.5±1.5 at 2.7 MPa. In this experiment we improved on the problem of temperature inhomogeneities by miniaturization of the sample cell.

Direct Observation of (110), (100) and (211) Facets on 3He Crystals

We present the results of our recent observations on 3He crystals grown from the superfluid phase at 0.55 mK. The crystal images were obtained with a low-temperature multiple-beam interferometer. The angles between the crystal facets were measured by employing a phase-shift technique and true 3D shapes of the crystals were reconstructed on the basis of the obtained information. Three different types of facets (110), (100) and (211) were clearly visible in these experiments.

Field Dependence of the Superfluid 3He A1 and A2 Transitions

AbstractWe present new results on the magnetic field dependence of the superfluid transition temperatures of the A1and A2phases of3He. The

Superfluid3He in high magnetic fields: New results

T_c^{A_1 }

Observations on Faceting of 3He Crystals at T=0.55 mK

transition temperature has been measured up to 15 T, the

Attenuation and velocity of first sound in a saturated 3He-4He mixture at very low temperatures and high magnetic field

T_c^{A_2 }