Spin-dependent electron transport in NiFe/GaAs Schottky barrier structures

Photoexcitation at the Schottky barrier formed between 5 nm thick Ni80Fe20 films and both n+- and p−-type GaAs(100) substrates with doping density in the range 1023⩽n(p)⩽1025 m−3 was investigated using circularly polarized laser light. A helicity-dependent photocurrent dependent upon the magnetization configuration of the film and the Schottky barrier height was detected. The results provide evidence of spin-dependent electron transport through the NiFe/GaAs interface and show that the Schottky barrier height controls the spin-dependent current passing from the semiconductor to the ferromagnet.