Dresden 2003 – wissenschaftliches Programm

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MA: Magnetismus

MA 14: Poster: Schichten(1-31), Spinabh.Trsp.(32-47), Exch.Bias(48-54), Spindyn.(55-64), Mikromag.(65-76), Partikel(77-88), Oflmag.(89-92), Spinelektr.(93-98), Elektr.Theo.(99-103), Mikromag+PhasÜ+Aniso.(104-122), MagnMat.(123-134), Messm+Mol-Mag.(135-139), Kondo(140-151)

MA 14.38: Poster

Dienstag, 25. März 2003, 15:15–19:15, Zelt

Fabrication and characterization of monocrystalline Fe/ZnSe/Fe tunnel contacts — •Martin Dumm, Johann Vancea, and Günther Bayreuther — Institut für Experimentelle und Angewandte Physik, Universität Regensburg, 93040 Regensburg

Theoretical work predicts high magneto-resistance values for monocrystalline tunnel contacts with semiconductor barriers. In order to fabricate a Fe/ZnSe/Fe trilayer, we start with an atomically flat GaAs(001) surface. On this surface a 20nm thick Fe(001) bottom layer is grown by molecular beam epitaxy (MBE). After annealing and Ar ion etching a smooth Fe surface is achieved, which is verified by scanning tunneling microscopy (STM). Afterwards the film is transferred into a second MBE chamber under UHV condition, where a ZnSe(001) film is grown by evaporation from a ZnSe compound source at a substrate temperature of 160^∘C - 200^∘C. High resolution transmission electron microscopy on cross sections shows the presence of some dislocations and the monocrystalline fcc structure of the ZnSe barrier. Auger electron spectroscopy depth profiles indicate a negligible interdiffusion between Fe and ZnSe. The epitaxial top Fe layer is again deposited in the metal MBE chamber. Both Fe layers have different magnetic coercive fields, which allow to produce an antiparallel magnetization configuration. Finally, electronic transport and magneto-transport across the tunnel barrier are discussed.