Superfluid3He in high magnetic fields: New results

The superfluid A₁ an A₂ transitions have been studied by means of vibrating wire viscosimeters in magnetic fields up to 9.3 T. Using the technique of quick melting of polarized solid (Castaing-Nozières effect) we have succeeded in increasing the superfluid transition temperature from 2.86 to 3.23 mK, which is the highest up to now. Using this method, with some improvements, it should be possible to test some of the present theoretical models for³He. A minimum of the viscosity in the A₁ phase has been observed for the first time. Very close to the A₂ transition an anomaly in the amplitude of the viscometers seems to indicate the presence of a new phase, or some textural change due to dipole locking.Invited talk at the International Conference on Macroscopic Quantum Phenomena, Smolenice Castle, Czechoslovakia, September 18–22, 1989.The authors wish to thank C. C. Kranenburg and C. M. C. M. van Woerkens for their various contributions to the experiments. Very helpful discussions with K. S. Bedell, B. Castaing, H. Capel, P. Nozières, D. Rainer, A. Schakel, and G. A. Vermeulen are gratefully acknowledged. This work was financially supported by the Stichting voor Fundamenteel Onderzoek der Materie F. O. M.