  We generate spin currents in an $^{87}$Rb spin-2 Bose-Einstein condensate by
application of a magnetic field gradient. The spin current destroys the spin
polarization, leading to a sudden onset of two-body collisions. In addition,
the spin coherence, as measured by the fringe contrast using Ramsey
interferometry, is reduced drastically but experiences a weak revival due to
in-trap oscillations. The spin current can be controlled using periodic $\pi$
pulses (bang-bang control), producing longer spin coherence times. Our results
show that spin coherence can be maintained even in the presence of spin
currents, with applications to quantum sensing in noisy environments.
