Search results for "MATERIA"
showing 10 items of 33501 documents
Development of hard x-ray photoelectron SPLEED-based spectrometer applicable for probing of buried magnetic layer valence states
2016
Abstract A novel design of high-voltage compatible polarimeter for spin-resolved hard X-ray photoelectron spectroscopy (Spin-HAXPES) went into operation at beamline BL09XU of SPring-8 in Hyogo, Japan. The detector is based on the well-established principle of electron diffraction from a W(001) single-crystal at a scattering energy of 103.5 eV. It's special feature is that it can be operated at a high negative bias potential up to 10 kV, necessary to access the HAXPES range. The polarimeter is operated behind a large hemispherical analyzer (Scienta R-4000). It was optimized for high transmission of the transfer optics. A delay-line detector (20 mm dia.) is positioned at the exit plane of the…
Refractive index controlled by film morphology and free carrier density in undoped ZnO through sol-pH variation
2018
Abstract Zinc oxide thin films, prepared by the sol-gel process, were deposited on glass substrate using spin coating technique. The sol-pH effect on the optical parameters was studied for alkaline sol. The surface roughness was investigated by atomic force microscopy (AFM) and varied from 20 to 40 nm. The optical transmission measurements were carried out to evaluate the behavior of the extinction coefficient and the refractive index. An exponential decay of the refractive index ‘n’ as a function of wavelength was observed. The refractive index increases slightly when the pH increases to pH = 9.5 where it reaches its maximum. Beyond this value, it decreases sharply. This behavior has been …
Determination of elastoplastic properties of TiO2 thin films deposited on dual phase stainless steel using nanoindentation tests
2010
International audience; In recent years, the extraction of mechanical behaviour of thin films by nanoindentation using sharp indenter geometry has been extensively studied. This work investigates the mechanical properties of TiO2 thin film (1 µm thickness) deposited by spin coating on dual phase Duplex stainless steel and glass substrates. Experiments are carried out with different sharp triangular pyramids (a Cube corner and a Berkovich indenter) using a commercial Nano Indenter® XP apparatus. The substrate effect has been counteracted and an inverse method proposed in literature for bulk material has been adapted to assess the elastoplastic parameters of the tested thin film directly from…
Enhancement of the Spin Pumping Effect by Magnon Confluence Process in YIG/Pt Bilayers
2019
The experimental investigation of the spin pumping process by dipolar‐exchange magnons parametrically excited in in‐plane magnetized yttrium iron garnet/platinum bilayers is presented. The electric voltage generated in the platinum layer via the inverse spin Hall effect (ISHE) results from contributions of two opposite spin currents formed by the longitudinal spin Seebeck effect and by the spin pumping from parametric magnons. In the field‐dependent measurements of the spin pumping‐induced component of the ISHE‐voltage, a clearly visible sharp peak is detected at high pumping powers. It is found that the peak position is determined by the process of confluence of two parametrically excited …
Luminescence characteristics of magnesium aluminate spinel crystals of different stoichiometry
2019
We are grateful to Drs E. Vasil’chenko and A. Maaroos for the help with experiments and useful discussions. This work has been carried out within the framework of the EUROfusion Consortium and has received funding from the Euratom research and training programme 2014-2018 under grant agreement No 633053. The views and opinions expressed herein do not necessarily reflect those of the European Commission. In addition, the research leading to these results has received funding from the Estonian Research Council Institutional Research Funding IUT02-26.
Diagrammatic Expansion for Positive Spectral Functions in the Steady-State Limit
2019
Recently, a method was presented for constructing self-energies within many-body perturbation theory that are guaranteed to produce a positive spectral function for equilibrium systems, by representing the self-energy as a product of half-diagrams on the forward and backward branches of the Keldysh contour. We derive an alternative half-diagram representation that is based on products of retarded diagrams. Our approach extends the method to systems out of equilibrium. When a steady-state limit exists, we show that our approach yields a positive definite spectral function in the frequency domain.
Synthesis of Eu<sup>2+</sup> and Dy<sup>3+</sup> Doped Strontium Aluminates and their Properties
2016
Strontium aluminate phosphors were synthesized by the solution combustion method using citric acid, urea or glycine as reducing agent and europium and dysprosium as dopants. The content of both dopants was in the range of 1 – 2 mol%. Dependence of phase composition, crystallite size and specific surface area on calcinations temperature, used reducing agents and dopants were determined. Luminescent properties of the calcinated at 1300 °C powders contained SrAl2O4 (90 %) and Sr4Al24O25 (10%) phases with crystallite size of 80 nm were determined.
Deposition of binder-free oxygen-vacancies NiCo2O4 based films with hollow microspheres via solution precursor thermal spray for supercapacitors
2019
Abstract Hollow micro-/nanostructures and oxygen vacancies are highly desirable for supercapacitors due to high active surface area and outstanding electrochemical properties. In order to benefiting from the both effect, binder-free oxygen-vacancies NiCo2O4 based films with hollow microspheres were pioneering directly deposited via one kind thermal spray technology, named solution precursor thermal spray (SPTS) process. To our best knowledge, the rapid one-step SPTS route was firstly employed to synthesize and deposit NiCo2O4 films for supercapacitor applications. The CV data clearly demonstrated that the specific capacitances of more oxygen-deficient NiCo2O4 electrodes with hollow microsph…
High transparency Bi 2 Se 3 topological insulator nanoribbon Josephson junctions with low resistive noise properties
2019
Bi$_2$Se$_3$ nanoribbons, grown by catalyst-free Physical Vapour Deposition, have been used to fabricate high quality Josephson junctions with Al superconducting electrodes. The conductance spectra (dI/dV) of the junctions show clear dip-peak structures characteristic of multiple Andreev reflections. The temperature dependence of the dip-peak features reveals a highly transparent Al/Bi$_2$Se$_3$ topological insulator nanoribbon interface and Josephson junction barrier. This is supported by the high values of the Bi$_2$Se$_3$ induced gap and of I$_c$R$_n$ (I$_c$ critical current, R$_n$ normal resistance of the junction) product both of the order of 160 $\mu$eV, a value close to the Al gap. T…
Color centers in diamond as novel probes of superconductivity
2018
Magnetic imaging using color centers in diamond through both scanning and wide-field methods offers a combination of unique capabilities for studying superconductivity, for example, enabling accurate vector magnetometry at high temperature or high pressure, with spatial resolution down to the nanometer scale. The paper briefly reviews various experimental modalities in this rapidly developing nascent field and provides an outlook towards possible future directions.