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We report the first observation of coherent precession of magnetization in superfluid 3He A-like phase (CP-A) in aerogel. The coherent precession in bulk 3He A-phase is unstable due to the positive feedback of spin supercurrent to the gradient of phase of precession. It was predicted that the homogeneous precession will be stable if the orbital momentum of the 3He A-phase can be oriented along the magnetic field. We have succeeded to prepare this configuration by emerging 3He in uniaxially deformed anisotropic aerogel. The dissipation rate of coherent precession states in aerogel is much larger than that in bulk 3He B-phase. We propose a mechanism of this dissipation.

Quantized vortices with half-integer circulation, which are forbidden from existing in a conventional superfluid because of the single valueness of the wave function, are theoretically predicted to exist in superfluid 3He-A if the order parameters l over and d over form l over perpendicular d over texture. To form the l over perpendicular d over texture, we confined the superfluid between parallel plates with a 12.5 microm gap and applied a magnetic field of H=26.7 mT perpendicular to the plates to take NMR and orient d over perpendicular to l over. NMR spectra exhibit a negative-shift peak which probes that the uniform l over perpendicular d over texture is realized in our cell and show a new satellite signal under rotation. The rotation dependence of the satellite signal is interpreted that a Fréedericksz transition of l over texture is induced by rotation above 1.0 rad/s and vortices start to appear above 1.8 rad/s.

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Unique types of textures and vortices of superfluid 3 He in restricted geometries have been discussed. We investigated cw-NMR in rotating 3 He A-phase in parallel plate geometries with gaps of 12.5 µm at 3.05 MPa. We observed a very sharp spectrum at rest which had shifted negatively as f = f L-0.93 f A (T), where f A (T) is the full transverse dipole shift in A-phase. The large negative shift of 0.93 f A (T) indicates that l d. When we rotated the sample with rotation speed Ω faster than the critical Ω Fr , a new satellite signal appeared nearly at f L. The satellite signal intensity increased with increasing Ω, reached a maximum at Ω c and slowly decreased up to the maximum Ω of 2π rad/s. When Ω decreased from the maximum speed, the satellite signal rapidly decreased and disappeared at 5.5 rad/s down to zero rad/s. We measured the temperature dependence of the satellite signal intensity, Ω Fr and Ω c. We propose a model for the satellite signal, which is attributed to spin wave in Fréedericksz transition region induced by the counter flow. We also compare the satellite signal with Kee and Maki's bound pair of HQV.