  Epitaxial ferromagnetic metal - semiconductor heterostructures are
investigated using polarization-dependent electroabsorption measurements on
GaAs p-type and n-type Schottky diodes with embedded In1-xGaxAs quantum wells.
We have conducted studies as a function of photon energy, bias voltage,
magnetic field, and excitation geometry. For optical pumping with circularly
polarized light at energies above the band edge of GaAs, photocurrents with
spin polarizations on the order of 1 % flow from the semiconductor to the
ferromagnet under reverse bias. For optical pumping at normal incidence, this
polarization may be enhanced significantly by resonant excitation at the
quantum well ground-state. Measurements in a side-pumping geometry, in which
the ferromagnet can be saturated in very low magnetic fields, show hysteresis
that is also consistent with spin-dependent transport. Magneto-optical effects
that influence these measurements are discussed.
