Experiments on magnetization in superfluid 3He

The results of a number of experiments on the dynamic and static magnetic properties of superfluids 3He-A and 3He-B are presented as well as a description of the 160-MHz rf-biased SQUID system used to make the magnetic flux measurements. Properties of both A and B phases were studied in both a rectangular cavity, a quasiideal geometry for 3He-A, and in a stack of parallel plates, a quasiideal geometry for 3He-B. The following results are presented: (1) Systematic studies of the properties of the ''wall-pinned'' magnetization ringing mode in 3He-B, including the zero time frequency, which shows a discrepancy with theory, and the relaxation, which tends to confirm the essence of the theoretical ideas; also included are a variety of data on the effect of the finite size of the magnetic field change and the ''biasing'' field. (2) A complicated propagating magnetic disturbance has been observed using a novel method and systematics of its properties are studied. (3) The linear ringing frequencies of the B and A phases at a pressure of 27.0 bar in the parallel plate geometry have been studied with a result consistent with the assignment of the ABM state to 3He-A and the BW state to 3He-B. (4) Nonlinear ringing has been studied in both A and B phases in both geometries for both the oscillatory and driven modes. In the limit 1-T/T/sub c/→0 we find 2πf/sub R//γΔHα2 for both phases in both geometries. Although the general character of ringing frequency f/sub R/ as a function of ΔH follows the theory, there are substantial quantitative discrepancies which cannot be explained by relaxation. (5) New measurements of static magnetism in the parallel plate geometry show agreement with all earlier work, indicating that the discrepancy between static and dynamic measurements cannot be explained by a geometrical effect. Manifestation of the AB interfacial energy enabled the coherence length to be estimated which is in qualitative agreement with theory