Search results for "polarization."
showing 10 items of 1842 documents
Observation of New Oscillatory Phenomena during the Electrochemical Anodization of Silicon
1999
This paper reports the observation of large undamped voltage oscillations during the anodic polarization of silicon in electrol yte containing a combination of acids. One of them stimulates oxide growth and the other its chemical dissolution (in the present c ase, (0.01-0.1 M H3PO4) + (0.001- 0.01 M HF). This temporal patterning of the anodization process is shown to be due to the formation of a thin (50-90 nm) oxide layer at the sample surface and its subsequent lifting-off. The mechanism of oxide detachment i s thought to be an isotropic growth of micropores at the oxide/silicon interface triggered on by changes of electrochemical condi tions there.
Phonon-induced spin relaxation of conduction electrons in silicon crystals
2014
Experimental works managing electrical injection of spin polarization in n-type and p-type silicon have been recently carried out up to room-temperature. In spite of these promising experimental results, a comprehensive theoretical framework concerning the influence of transport conditions on phonon-induced electron spin depolarization in silicon structures, in a wide range of values of lattice temperature, doping concentration and amplitude of external fields, is still at a developing stage. In order to investigate the spin transport of conduction electrons in lightly doped n-type Si crystals, a set of semiclassical multiparticle Monte Carlo simulations has been carried out. The mean spin …
Polarization insensitive wavelength conversion of 40 Gb/s DPSK signals in a silicon germanium waveguide
2015
We demonstrate polarization insensitive FWM-based wavelength conversion of 40Gb/s DPSK signals in a SiGe waveguide, with 0.42-dB polarization-dependent loss. A 1.5-dB Dower nenaltv was measured at a BER of 10−9.
Mapping the polarization pattern of plasmon modes reveals nanoparticle symmetry.
2008
We study the wavelength and polarization dependent plasmon resonances of single silver and gold nanorods, triangles, cubes, and dimers with a novel single particle spectroscopy method (RotPOL). In RotPOL, a rotating wedge-shaped polarizer encodes the full polarization information of each particle within one image. This reveals the symmetry of the particles and their plasmon modes, allows analyzing inhomogeneous samples and the monitoring of particle shape changes during growth in situ.
Preparation of Heusler thin films: The quaternary alloy CO2Fe0.5Mn0.5Si
2008
In this work the basic strategies for the preparation of CO2Mn0.5Fe0.5Si as an example for Heusler alloy thin films will be described. Texture and magnetic properties of these films will be discussed, especially with regard to different buffer layers and annealing temperatures. Finally, we will show the integration of Heusler thin films into magnetic tunnel junctions (MTJs) and calculate the effective spin polarization. (c) 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Preparation and Investigation of Interfaces of Co2Cr1−x Fe x Al Thin Films
2013
In the framework of spin polarization investigations of Heusler compounds by the measurement of the magnetoresistance (TMR) of tunneling junctions with AlO x barrier special emphasis is put on the role of the interfaces.
Spin-resolved terahertz spectroscopy
2016
As such, terahertz spectroscopy cannot resolve the spin structure of conducting particles. Here we introduce the spin sensitivity to terahertz spectroscopy by using the spin-valve configuration of the sample. As a result, the number density and momentum scattering time of conduction electrons in a ferromagnetic metal can be resolved according to their spin.
Epitaxial film growth and magnetic properties ofCo2FeSi
2006
We have grown thin films of the Heusler compound ${\mathrm{Co}}_{2}\mathrm{Fe}\mathrm{Si}$ by RF magnetron sputtering. On (100)-oriented MgO substrates we find fully epitaxial (100)-oriented and $L{2}_{1}$ ordered growth. On ${\mathrm{Al}}_{2}{\mathrm{O}}_{3}(11\overline{2}0)$ substrates, the film growth is (110)-oriented, and several in-plane epitaxial domains are observed. The temperature dependence of the electrical resistivity shows a power law with an exponent of $7∕2$ at low temperatures. Investigation of the bulk magnetic properties reveals an extrapolated saturation magnetization of $5.0{\ensuremath{\mu}}_{B}∕\mathrm{f.u.}$ at $0\phantom{\rule{0.3em}{0ex}}\mathrm{K}$. The films on $…
Lattice Instability and Competing Spin Structures in the Double Perovskite InsulatorSr2FeOsO6
2013
The semiconductor Sr2FeOsO6, depending on temperature, adopts two types of spin structures that differ in the spin sequence of ferrimagnetic iron-osmium layers along the tetragonal c axis. Neutron powder diffraction experiments, 57Fe Mossbauer spectra, and density functional theory calculations suggest that this behavior arises because a lattice instability resulting in alternating iron-osmium distances fine-tunes the balance of competing exchange interactions. Thus, Sr2FeOsO6 is an example of a double perovskite, in which the electronic phases are controlled by the interplay of spin, orbital, and lattice degrees of freedom.
Spin-polarized photoelectrons resonantly excited by circularly polarized light from a fractional Ag film on GaAs(100)
2013
We demonstrate a finite spin polarization of photoelectrons emitted from GaAs(100) covered by a fractional Ag film. The photoemission yield shows a sharp maximum for intermediate coverage and the spin polarization increases with increasing laser intensity. Photoelectrons are excited by circularly polarized 100 fs laser pulses of 800 nm wavelength. We recorded the photoemitted electrons using a photoemission electron microscope combined with a Mott spin polarimeter. The spin polarization is analyzed in dependence on the excitation frequency and intensity and on the average thickness of the silver film. The results are explained by a model combining multiphoton photoemission and optical field…