AVS 46th International Symposium
    Magnetic Interfaces and Nanostructures Technical Group Wednesday Sessions
       Session MI+EM-WeM

Paper MI+EM-WeM11
Electron Spin Interferometry

Wednesday, October 27, 1999, 11:40 am, Room 618/619

Session: Spin-Dependent Tunneling and Transport
Presenter: C.H. Back, ETH Zürich, Switzerland
Authors: C.H. Back, ETH Zürich, Switzerland
S. Egger, ETH Zürich, Switzerland
J. Krewer, Blaupunkt-Werke GmbH, Germany
D. Pescia, ETH Zürich, Switzerland
Correspondent: Click to Email
Quantum interference of electron waves in Fabry-Perot type solid-state resonators has been observed in a number of experiments. The applications of this phenomenon include quantum-well based semiconductor devices,@footnote 1@ accurate mapping of the band structure of solids and surfaces@footnote 2,3,4,5@ and visualizing the spatial dependence of quantum mechanical wave functions by means of Scanning Tunnelling Spectroscopy (STS).@footnote 5@ Here we use quantum interference to switch the spin state of the electrons. The spin quantum resonator consists of a Cu-film of variable thickness sandwiched between vacuum and a magnetic Co-film. Electrons are injected into the resonator from the vacuum side. The Co-film provides a spin dependent reflector. Varying the resonator thickness results in periodic switching of the spin state of the specularly reflected electrons. We apply spin interferometry to study oscillatory interlayer exchange coupling and find a divergence of the coupling period predicted by theory.@footnote 6@ We discuss the implications of spin interferometry as spin polarimeter or spin polarized source and propose that interferometric spin selection should be observable in Spin Polarized STS. @FootnoteText@@footnote 1@Corcoran, E., Diminishing Dimensions, Sci.Am. 263, p.74-83, November Issue, (1990). @footnote 2@Paggel, J.J., Miller, T., Chiang, T.-C., Quasiparticle Lifetime in Macroscopically Uniform Ag/Fe(100) quantum Wells, Phys.Rev.Lett.81, 5632-5635, (1998). @footnote 3@Ortega, J.E., Himpsel, F.J., Mankey G.J., Willis, R.F., Quantum-well states and magnetic coupling between ferromagnets through a noble-metal layer, Phys.Rev.B 47, 1540-1552 (1993). @footnote 4@Kawakami, R.K. et al., Quantum-well states in copper thin films, Nature 398, 132-134 (1999). @footnote 5@Crommie, M.F., Lutz, C.P., Eigler, D.M., Imaging standing waves in a two-dimensional electron gas, Nature 363, 524-527 (1993). @footnote 6@Edwards,D.M., Mathon, J., Oscillations in exchange coupling across a nonmagnetic metallic layer, J.Magn.Magn.Mat. 93, 85-88 (1991).