Homogeneously precessing domain in 3He-B: formation and properties

The long-range order realized in the superfluid phases of He-3 leads to a nonlocal motion of spin in these phases. In the B phase the nonlocality manifests itself in the formation of a homogeneously precessing domain (HPD). This domain is formed under conditions of nuclear magnetic resonance. Within the domain spin precesses coherently-with the same frequency and phase even though the steady magnetic field can be nonuniform. Coherence of precession is maintained by the spin current carried by the condensate of Cooper pairs. The key experiments, revealing the main properties of the HPD and the underlying theory are briefly reviewed in this paper.