Torsional oscillator studies of rotating [formula omitted]-A in a slab

Abstract

Using a rotating cryostat we have manipulated l-textures of 3 He -A in a 0.26 mm -thick slab contained in a torsional oscillator. Application of a magnetic field or a counterflow due to rotation lead to a sudden distortion of a uniform texture. The uniformity of the initial texture can be characterized by the resulting shift in frequency and bandwidth of the torsional resonance. With a certain density of vortices induced by rotation a uniform texture can be stabilized even in presence of magnetic. The optimal speed of rotation to prepare a uniform texture while cooling through T c was found. The critical velocities for the flow-induced textural transition and vortex nucleation are determined.