Electron-spin motion: a new tool to study ferromagnetic films and surfaces

Abstract

We analyze the behavior of the four-terminal resistance, relative to the two-terminal resistance of an interacting quantum wire with an impurity, taking into account the invasiveness of the voltage probes. We consider a one-dimensional Luttinger model of spinless fermions for the wire. We treat the coupling to the voltage probes perturbatively, within the framework of non-equilibrium Green function techniques. Our investigation unveils the combined effect of impurities, electron-electron interactions and invasiveness of the probes on the possible occurrence of negative resistance.

Breakdown of the electron-spin motion upon reflection at metal-organic or metal-carbon interfaces. II.

“…1 for the exchange-governed case). We emphasize that the spindependent reflectivity can also be studied by measurements in which P 0 is parallel or antiparallel to M or n. In this case a reflectivity or intensity asymmetry A can be measured which is directly related to the rotation angle φ in a spin-motion experiment [5]. The precession angle ε, however, cannot be determined within such an experiment.…”

“…The top inset shows the two types of motion of the spin-polarization vector. If the initial spin polarization P 0 is oriented perpendicularly with respect to the magnetization M of the ferromagnet the spin polarization precesses around M by an angle ε and rotates simultaneously in the plane P-M by an angle φ.T h e precession angle is the difference of the spin-dependent reflection phases and the rotation angle is determined by the difference of the spin-dependent reflectivities [2,5]. Consequently, electron reflection becomes independent of the spin when both quantities disappear which is the case for Pc thicknesses already well below 1 ML.…”

Co and Phthalocyanine Overlayers on the Quantum-Well System Co(001)/Cu: Spin-Polarized Electron Reflection Experiments

“…It has already been shown by Egger et al [28] that the very pronounced structures of A ex as a function of Cu thickness in the system Co(001)/Cu are directly related to the presence of QWR in the Cu film. In a later work [25] the Cu-thickness dependent behavior of the spin motion angle φ, which is directly related to the quantity A ex [29], has been studied. Most importantly, the energy positions of the extrema in φ and thus in A ex shift with varying Cu film thickness and are in good agreement with those of the extrema in reflectivity.…”