Spin-dependent thermopower in Co/Cu multilayer nanowires

Chat with Graph Search

Ask any question about EPFL courses, lectures, exercises, research, news, etc. or try the example questions below.

DISCLAIMER: The Graph Chatbot is not programmed to provide explicit or categorical answers to your questions. Rather, it transforms your questions into API requests that are distributed across the various IT services officially administered by EPFL. Its purpose is solely to collect and recommend relevant references to content that you can explore to help you answer your questions.

We propose a novel thermometric technique for measuring absolute temperature in gas media based on Brillouin scattering. The method retrieves the temperature from the acoustic velocity of the gas, inferred through the spectral shift experienced by a scattered laser beam during the Brillouin acousto-optic interaction. This approach is inherently contactless, enabling remote sensing applications with high precision. It also exhibits enhanced sensitivity in the cryogenic range and is fully compatible with dist

Magnetic‐field enhancement of the oxygen evolution reaction (OER) represents a promising route toward more efficient alkaline water electrolyzers, yet its origin remains debated due to overlapping effects of mass transport and reaction kinetics. Here, we present a general experimental strategy that employs strong forced convection to suppress uncontrolled transport arising from natural diffusion and magnetohydrodynamic (MHD) flows. Using polycrystalline Au electrodes, we show that this approach resolves sub

We present the results of 3D, flux-driven, global, two-fluid electrostatic turbulence simulations in a 5-field period stellarator with an island divertor. The numerical simulations are carried out with the GBS code, which solves the two-fluid drift-reduced Braginskii equations and has been extended recently to simulate plasma turbulence in non-axisymmetric magnetic equilibria. The vacuum magnetic field used in the simulations is carefully constructed using Dommaschk potentials in order to describe a configu

Depending on the materials and processing parameters, composite materials consisting of an insulating matrix and a conductive filler may be electrically insulating, resistive or conducting. Previously, we had manufactured composites consisting of a resin and a conducting magnetic filler, and shown that polymerisation under magnetic field could achieve oriented conductors, with essentially unidirectional electrical conduction. In this work, we explore the possibility of replacing the resin matrix by a thermo

Strain response of polycrystalline barium titanate (BaTiO3) was investigated under high unipolar electric field (0 to 4 kV/mm) and compressive stress (0 to 400 MPa) in the temperature range from 25 to 160 degrees C. In the vicinity of the Curie point (T-C), nonlinear and hysteretic strain-electric field and strain-stress constitutive behaviors were observed, persisting above T-C where they correspond to the well-known electric field induced double loop polarization behavior. Analogous to the electrical doub

The origin of pairing in a superconductor resides in the underlying normal state. In the cuprate high-temperature superconductor YBa2Cu 3Oy (YBCO), application of a magnetic field to suppress superconductivity reveals a ground state that appears to break the translational symmetry of the lattice, pointing to some density-wave order. Here we use a comparative study of thermoelectric transport in the cuprates YBCO and La 1.8-xEu0.2SrxCuO4(Eu-LSCO) to show that the two materials exhibit the same process of Fer

The Nernst coefficient of the cuprate superconductor YBa2Cu 3Oy was recently shown to become strongly anisotropic within the basal plane when cooled below the pseudogap temperature T, revealing that the pseudogap phase breaks the fourfold rotational symmetry of the CuO 2 planes. Here we report on the evolution of this Nernst anisotropy at low temperature, once superconductivity is suppressed by a magnetic field. We find that the anisotropy drops rapidly below 80 K, to vanish in the T=0 limit. We show that t

Magnetic resonance imaging (MRI) is one of the most powerful diagnostic techniques used in clinics. The need for higher spatial resoln. and better sensitivity led to the development of imagers working at high magnetic fields. The routine clin. use of 3 T MR systems raised the demand for MRI contrast agents working at this field or above. In the following we summarize the research in our research group on such high-field contrast agents.

Several geometries have recently been proposed for spin-transfer oscillators, with the purpose of optimizing the output power and the frequency dependence on the applied current, as well as minimizing the external magnetic field required to stabilize magnetization dynamics. The two structures most compatible with applications involve hybrid multilayers, including magnetic films magnetized in the plane, as well as perpendicular to the plane of the layers - alternatively acting as polarizing layer for the cur

The Seebeck and Nernst coefficients S and ν of the cuprate superconductor YBa2Cu3Oy (YBCO) were measured in a single crystal with doping p=0.12 in magnetic fields up to H=28T. Down to T=9 K, ν becomes independent of field by H 30T, showing that superconducting fluctuations have become negligible. In this field-induced normal state, S/T and ν/T are both large and negative in the T→0 limit, with the magnitude and sign of S/T consistent with the small electronlike Fermi surface pocket detected previously by qu

We investigate in this work the fabrication of polymer micro-fluidic and micro-mechanical devices based on sublimable compounds as sacrificial layers, using a thick-film screen-printing deposition process. Fabrication of printed polymer microstructures featuring properties such as low cost, transparency and biocompatibility is particularly attractive and suitable for disposable biomedical devices. Channel, cavities and spacings for micro-devices are first defined by sacrificial material layers. This is foll

The aim of this thesis work is to study the spin-dependent transport in multiwalled carbon nanotubes (MWNT). To do so, the electrical resistance of MWNT contacted between ferromagnetic electrodes has been measured, as a function of the contacts magnetic configuration and temperature. An original sample fabrication process to contact MWNT has been developed. The MWNT growth is achieved via chemical vapour deposition in the pores of an alumina template, with electrodeposited nickel or cobalt nanowires as cata

Recently, engineering return stroke models were extended to take into account the presence of an elevated strike object, which was modeled as an ideal uniform transmission line. We show in this paper that the current distribution associated with these extended models exhibits a discontinuity at the return stroke wave front, which cannot be considered to be physically plausible. This discontinuity arises from the fact that the current injected into the tower from its top is reflected back and forth at its en

There is currently both considerable interest in the physics of ELM transport in the scrape-off layer (SOL) and concern over the impact of the ELM power and particle loads on the divertor targets of future fusion reactors. This paper describes some experimental observations of the reaction of target floating potentials and currents during ELMS in TCV, relying principally on fast measurements of these parameters using tile embedded Langmuir probe arrays. Clear evidence is presented for rapid modifications in

One view of the high-transition-temperature (high-T-c) copper oxide superconductors is that they are conventional superconductors where the pairing occurs between weakly interacting quasi-particles (corresponding to the electrons in ordinary metals), although the theory has to be pushed to its limit(1). An alternative view is that the electrons organize into collective textures (for example, charge and spin stripes) which cannot be 'mapped' onto the electrons in ordinary metals. Understanding the properties

The thermoforming of thermoplastic sandwich structures based on the same matrix polymer for the face sheets and the core requires precise temperature control both before and during forming. Two opposing requirements must be satisfied: the face sheets must be heated to above the glass transition temperature Tg of the polymer whereas the temperature of the core should not approach Tg in order to avoid the collapse of the foam cells. A numerical model was used to determine the optimal thermal parameters for th

We report on the electric field effects in photoluminescence (PL) and PL excitation (PLE) measurements of reverse-biased GaAs V-groove quantum wires. We observe large redshifts (9 meV at 265 kV/cm) of PL and PLE peaks as well as field dependent intensity and polarization anisotropy variations, which are analyzed by a two-dimensional quantum confined Stark effect model. (C) 1999 American Institute of Physics. [S0003-6951(99)00416-7].

In the first part of this work a comprehensive model of the continuous hardening of 3D-axisymmetric steel components by induction heating has been developed. In the model, the Maxwell and heat flow equations are solved using a mixed numerical formulation : the inductor and the workpiece are enmeshed with finite elements (FE) but boundary elements (BE) are used for the solution of the electromagnetic equations in the ambient air. This method allows the inductor to be moved with respect to the workpiece witho

We review, from a unified point of view, a general class of models of itinerant electrons interacting with classical fields. Applications to the static Holstein, Kondo, and Hubbard models are discussed. The ground state structure of the classical field is investigated when the electron band is half-filled. Some of the results are also valid when there is a Hubbard interaction between spin up and spin down electrons. It is found that the ground states are either homogeneous or period two Ne´el configurations

Quantum wire heterostructures, such as V- and T-shaped wires, are very promising candidates for low-threshold lasing. A crucial issue is the excitonic vs. free-carrier nature of the radiative recombination. Here, we report on magnetophotoluminescence studies of GaAs and InGaAs V-shaped wires that allow to discriminate different regimes of radiative recombination.

Spin-dependent thermopower in Co/Cu multilayer nanowires

Chat with Graph Search

Absolute thermometry based on Brillouin scattering in gases

Quantifying the Reduction of OER Overpotential on Magnetic Electrocatalysts Under Magnetic Fields

First global simulations of plasma turbulence in a stellarator with an island divertor

Magnetically tuneable thermoplastic resistive composites

Critical mechanical and electrical transition behavior of BaTiO3: The observation of mechanical double loop behavior

Fermi-surface reconstruction by stripe order in cuprate superconductors

Nernst effect in the cuprate superconductor YBa_{2}Cu_{3}O_{y}: Broken rotational and translational symmetries

The challenge of T1 contrast agents for high-magnetic field MRI

Different geometries for spin-transfer oscillators

Nernst and Seebeck Coefficients of the Cuprate Superconductor YBa_{2}Cu_{3}O_{6.67}: A Study of Fermi Surface Reconstruction

Fabrication of polymer micro-devices based on organic sacrificial pastes

Longueur de diffusion de spin et magnétisme de structures nanotubes de carbone / matériaux ferromagnétiques

Electromagnetic field radiated by lightning to tall towers: treatment of the discontinuity at the return stroke wave front

ELM driven divertor target currents on TCV

Antiferromagnetic order induced by an applied magnetic field in a high-temperature superconductor

Pre-Heating of Thermoplastic Sandwich Materials for Rapid Thermoforming

Two-dimensional quantum-confined Stark effect in V-groove quantum wires: Excited state spectroscopy and theory

Modélisation des transformations de phase à l'état solide dans les aciers et application au traitement thermique par induction

Ground states and low temperature phases of itinerant electrons interacting with classical fields: a review of rigorous results

Magnetic-field effects in the luminescence of V-shaped quantum wires