Spin filtering in a hybrid ferromagnetic-semiconductor microstructure
  We fabricated a hybrid structure in which cobalt and permalloy micromagnets produce a local in-plane spin-dependent potential barrier for high-mobility electrons at the GaAs/AlGaAs interface. Spin effects are observed in ballistic transport in the tens' millitesla range of the external field, and are attributed to switching between Zeeman and Stern-Gerlach modes -- the former dominating at low electron densities. 
J. Wr\'obel, T. Dietl, A. Lusakowski, G. Grabecki, K. Fronc, R. Hey,   K. H. Ploog, H. Shtrikman