  A novel spin-spin coupling mechanism that occurs during the transport of
spin-polarized minority electrons in semiconductors is described. Unlike the
Coulomb spin drag, this coupling arises from the ambipolar electric field which
is created by the differential movement of the photoelectrons and the
photoholes. Like the Coulomb spin drag, it is a pure spin coupling that does
not affect charge diffusion. Experimentally, the coupling is studied in $p^+$
GaAs using polarized microluminescence. The coupling manifests itself as an
excitation power dependent reduction in the spin polarization at the excitation
spot \textit{without} any change of the spatially averaged spin polarization.
