Browsing by Subject "Atomic, molecular and chemical physics"
Now showing items 1-20 of 92
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1/f noise in MgO double-barrier magnetic tunnel junctions
(2011)Low frequency noise has been investigated in MgO double-barrier magnetic tunnel junctions (DMTJs) with tunneling magnetoresistance (TMR) ratios up to 250% at room temperature. The noise shows a 1/f frequency spectrum and ... -
Ab initio study of electron transport in dry poly(G)-poly(C) A-DNA strands
(2010)The bias-dependent transport properties of short poly (G)-poly(C) A-DNA strands attached to Au electrodes are investigated with first-principles electronic-transport methods. By using the nonequilibrium Green's function ... -
Anomalous I-V curve for mono-atomic carbon chains
(2010)The electronic transport properties of mono-atomic carbon chains were studied theoretically using a combination of density functional theory and the non-equilibrium Green's functions method. The I?V curves for the chains ... -
Anomalous strain relaxation behaviour of Fe3O4/MgO (100) heteroepitaxial system grown using molecular beam epitaxy
(2006)Strain relaxation studies in epitaxial magnetite (Fe3O4) thin films grown on MgO (100) substrates using high-resolution x-ray diffraction and cross-sectional transmission electron microscopy reveal that the films remain ... -
Antiferromagnetic interlayer exchange coupling between Fe3O4 layers across a nonmagnetic MgO dielectric layer
(2008)We have investigated the interlayer exchange coupling between the epitaxial spinel Fe3O4 layers across an insulating nonmagnetic MgO spacer. The epitaxial structure used for these investigations was Fe3O4 (10?nm)/MgO ... -
Asymmetry effects in atomically resolved STM images of Cu (014)-O and W (100)-O surfaces measured with MnNi tips
(2007)We report on scanning tunneling microscopy (STM) studies of the Cu(014)-O and W(100)-O surfaces using MnNi tips. The STM data demonstrate asymmetry effects in atomically resolved images of W(100)-O as well as a regular ... -
Atomic row doubling in the STM images of Cu(014)-O obtained with MnNi tips
(2007)We report on scanning tunneling microscopy studies of the Cu(014)-O surface using MnNi tips. Remarkably, the results show a regular apparent doubling of surface atomic rows in the {110} direction. A qualitative explanation ... -
BCS-BEC crossover in a system of microcavity polaritons
(American Physical Society, 2005)We investigate the thermodynamics and signatures of a polariton condensate over a range of densities, using a model of microcavity polaritons with internal structure. We determine a phase diagram for this system including ... -
Boron diffusion in magnetic tunnel junctions with MgO (001) barriers and CoFeB electrodes
(2010)Boron diffusion out of the CoFeB layers in model systems with thick CoFeB and MgO layers grown by radiofrequency sputtering or electron-beam evaporation and in MgO-based magnetic tunnel junctions (MTJs) is probed after ... -
Breakdown of counterflow superfluidity in a disordered quantum Hall bilayer
(2011)We present a theory for the regime of coherent interlayer tunneling in a disordered quantum Hall bilayer at total filling factor one, allowing for the effect of static vortices. We find that the system consists of domains ... -
Charge freezing and surface anisotropy on magnetite (100)
(1993)Scanning tunneling microscope images of the (100) surface of slightly nonstoichiometric magnetite taken at room temperature show static arrays of pairs of Fe2+ ions with short?range order, and a charge fluctuation time ... -
Charge ordering on the surface of Fe3O4(001)
(2002)We have studied the (001) surface of a Fe3O4 single crystal using scanning tunneling microscopy (STM), low-energy electron diffraction (LEED), and Auger electron spectroscopy. A clean surface was obtained by a combination ... -
Compact 2-D FDTD Method Combined With Pad Approximation Transform for Leaky Mode Analysis
(2010)Leaky mode analysis has been carried out based on the compact 2-D finite-difference time-domain (FDTD) method combined with the uniaxial anisotropic perfectly matched-layer (UPML) absorption boundary condition and the Pade ... -
Concept of a nanowire array magnetoresistance device
(2008)We describe a concept of the magnetoresistive medium comprising of a planar array of intermingled nanowires with pinned and unpinned magnetic moments. We propose a bottom up method of forming the medium and demonstrate the ... -
Condensation and lasing of microcavity polaritons: comparison between two models
(Elsevier, 2005)Condensation of microcavity polaritons and the substantial influence of pair-breaking disorder and decoherence leading to a laser regime has been recently considered using two different models: a model for direct two ... -
Conductance of a phenylene-vinylene molecular wire: Contact gap and tilt angle dependence
(2010)Charge transport through a molecular junction comprising an oligomer of p-phenylene-vinylene between gold contacts has been investigated using density-functional theory and the nonequilibrium Green?s function method. The ... -
Damping dependence of the reversal time of the magnetization of single-domain ferromagnetic particles for the Neel-Brown model: Langevin dynamics simulations versus analytic results
(American Physical Society, 2010)The damping dependence of the thermally activated reversal time of the magnetization of noninteracting uniaxial single-domain ferromagnetic particles is determined using Langevin dynamics simulations and the analytic ... -
Dynamic behavior of a piezowalker, inertial and frictional configurations
(American Institute of Physics, 1999)We have examined two configurations of a piezowalker, the inertial and the frictional one, both of which are capable of moving samples with submicrometer steps over a distance of some millimeters. We demonstrated that, ... -
Effect of epitaxial strain on the cation distribution in spinel ferrites CoFe(2)O(4) and NiFe(2)O(4): A density functional theory study
(American Institute of Physics, 2011)The effect of epitaxial strain on the cation distribution in spinel ferrites CoFe(2)O(4) and NiFe(2)O(4) is investigated by GGA+U total energy calculations. We obtain a very strong (moderate) tendency for cation inversion ... -
Electrically driven phase transition inmagnetite nanostructurers
(NATURE PUBLISHING GROUP, 2008-02)Magnetite (Fe3O4), an archetypal transition-metal oxide, has been used for thousands of years, from lodestones in primitive compasses(1) to a candidate material for magnetoelectronic devices(2). In 1939, Verwey(3) found ...