PERSISTENT SPIN PRECESSION IN HE-3-B IN THE REGIME OF VANISHING QUASI-PARTICLE DENSITY

We describe the observation of an extremely long-lived induction decay signal of the precession of the magnetization in superfluid He-3-B. This is probably the first evidence of the formation of a coherent quantum magnetic state with deflected magnetization. This state can be excited at a frequency of 1 MHz at temperatures of about 0.1 T(c) and has been observed to persist for periods up to 25 s. The properties are entirely distinct from those of the well-known long-lived induction decay signal arising from a homogeneously precessing domain.