Magnetically stabilized AB interface in rotating superfluid 3He

Abstract How do vortex lines in the A and B phases of superfluid 3 He interact at the AB phase boundary, when they have different structure and quantization in these two phases? We discuss an experimental setup where the AB interface is stabilized in a long cylindrical sample with a magnetic barrier field. It divides the sample in A- and B-phase sections which are maintained in homogeneous low-field NMR environments over the temperature interval where the supercooled A phase exists. With two independent NMR spectrometers the vortex lines in the two phases can be studied as a function of the rotation velocity of the cryostat. Simultaneously, by adjusting the barrier field and temperature, the sample can be changed from single phase to two-phase configurations, or to one with two AB interfaces. Using this setup the first example of a shear-flow instability in superfluids was discovered (Phys. Rev. Lett. 89 (2002) 155 301).