Spin-polarized electron transport in ferromagnet/semiconductor hybrid structures induced by photon excitation - art. no. 104425

Circularly polarized light was used to excite electrons with a spin polariz ation perpendicular to the film plane in 3 mm Au/5 nm Ni80Fe20/GaAs(100) st ructures with doping density in the range 10(23) to 10(25) m(-3). At negati ve bias a helicity-dependent photocurrent dependent upon the magnetization configuration of the film and the Schottky barrier height was detected. The helicity-dependent photocurrent polarization decreases with increasing dop ing density and has the same variation with photon energy as found fur the polarization of photoexcited electrons in GaAs. The results provide unambig uous evidence of spin-dependent electron transport through the NiFe/GaAs in terface and show that the Schottky barrier height controls the spin-depende nt electron current passing from the semiconductor to the ferromagnet.