  We report on the detailed study of multi-component spin-waves in an s=3/2
Fermi gas where the high spin leads to novel tensorial degrees of freedom
compared to s = 1/2 systems. The excitations of a spin-nematic state are
investigated from the linear to the nonlinear regime, where the tensorial
character is particularly pronounced. By tuning the initial state we engineer
the tensorial spin-wave character, such that the magnitude and sign of the
counterflow spin-currents are effectively controlled. A comparison of our data
with numerical and analytical results shows excellent agreement.
