Regensburg 2004 – wissenschaftliches Programm

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MA: Magnetismus

MA 13: Poster:Schichten(1-23),Spinabh.Trsp(24-41),Exch.Bias(42-56),Spindyn.(57-67),Mikromag.(68-76),Partikel(77-90),Spinelektr.(91-97),Elektr.Theo.(98-99),Mikromag+PhasÜ+Aniso.(100-105),Magn.Mat.(106-118),Messmethod.(119-121),Obflm.+Abbverf.(122-123)

MA 13.31: Poster

Dienstag, 9. März 2004, 15:00–19:00, Bereich A

Fabrication and charakterization of monocrystalline Fe/ZnSe/Fe tunnel contacts — •Martin Dumm 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. Fe/ZnSe/Fe trilayers have been fabricated by molecular beam epitaxy (MBE) using two separate MBE-Systems, where the samples can be transferred from one chamber to the other without breaking the vacuum using a portable UHV chamber. High resolution transmission electron microscopy on cross sections and reflective high energy electron diffraction prove that the whole system is grown epitaxially on the GaAs(001) substrate. The 20nm thick Fe bottom layer has a dominating fourfold magnetic anisotropy with the easy axes along [100] and [010], whereas a uniaxial anisotropy with easy axis along [110] prevails in the 2nm thick Fe top layer. Magnetization loops for the Fe/ZnSe/Fe show that the coercive field of the top layer is smaller than that of the bottom layer between 300K and 80K, whereas below 80K both Fe films switch at the same magnetic field. This means that at low temperature the switching of the thinner top layer is triggered by the switching of the thicker bottom layer.

Finally, first magneto-transport measurements across the tunnel barrier at 100K are reported.