共查询到20条相似文献,搜索用时 11 毫秒
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Energy losses due to the excitation of surface guided waves have been observed in inelastic electron scattering from thin films of aluminum oxide. 相似文献
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Hans-Joachim Freund 《Surface science》2007,601(6):1438-1442
Thin oxide films lend themselves as model supports for studies in heterogeneous catalysis, for example, to study the growth and reaction of metal deposits (atoms, clusters and nanoparticles). If the thickness of the film is chosen appropriately these thin films are reasonable models to mimic the situation of bulk materials. If thin films below a critical thickness are studied these materials exhibit properties in their own right. Their structural properties may be tuned to control their functional characteristics. Possible implications for heterogeneous catalysis are discussed. 相似文献
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By capacitively charging an underdoped ultrathin La2-xSrxCuO4 film with an electric field applied across a gate insulator with a high dielectric constant, relative changes of the areal superfluid density ns of unprecedented strength were observed in measurements of the film kinetic inductance. Although ns appears to be substantially reduced by disorder, the data provide, for the first time on the same sample, direct compelling evidence for the Uemura relation Tc proportional to ns(T=0) in the underdoped regime of copper-oxide superconductors. 相似文献
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《Journal of magnetism and magnetic materials》1995,150(1):L5-L12
We present a dynamical study of hysteresis loops of a MoS2/[Au/Co/Au] sandwich performed by surface magneto-optical Kerr effect with a field variation rate up to 1.2 MOe/s. An interpretation of dynamical effects at room temperature is proposed, using a modelization of the magnetization reversal. We discuss simulations which describe two different processes of the magnetization reversal to interpret the evolution of the hysteresis loops for several rates of variation of the magnetic field. For a first range of field variation rates lower than 180 kOe/s, the predominant mechanism seems to be wall motion and beyond 180 kOe/s, an expression for the magnetization is given, which supposes micro-domains reversal as a prevailing process. Finally, the general behaviour of the relaxation time, depending on the magnetic field, is investigated. 相似文献
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A stripe domain structure (DS) was studied in an ultrathin ferromagnetic film under an in-plane magnetic field. The basic structure parameters (the amplitude and period of the DS, the thickness of domain walls) were determined within a unified variational approach, and transitions from the DS state to a homogeneous canted and a homogeneous planar phase were studied. 相似文献
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The influence of a deformational defect of the shear modulus on the melting of an ultrathin lubricant film was investigated in the framework of the Lorenz model used for describing a viscoelastic medium. It was established that the film can undergo both stepwise and continuous melting. Analysis of the lubricant behavior revealed that there are three modes corresponding to a zero shear stress, a Hookean portion in the loading diagram, and a plastic-flow portion. The hysteresis in the dependences of the stationary shear stress on the strain and the friction surface temperature is examined. 相似文献
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I. I. Pronin M. V. Gomoyunova D. E. Malygin D. V. Vyalykh Yu. S. Dedkov S. L. Molodtsov 《Physics of the Solid State》2008,50(3):553-556
The effect of magnetic linear dichroism in photoemission of Fe 3p electrons was used to investigate the magnetic properties of the Si(100)2 × 1 surface on which iron films up to 10 monolayers thick were deposited at room temperature under ultrahigh vacuum. The experiments were performed with linearly polarized light (at a photon energy of 135 eV) incident at an angle of 30° to the surface. The photoelectron spectra were measured in a narrow solid angle oriented along the normal to the sample surface for two opposite magnetization directions which were parallel to the surface plane and perpendicular to the polarization vector of the light wave. An analysis of the data obtained showed that the effect has a threshold character and appears after deposition of eight Fe monolayers, when the ferromagnetic silicide Fe3Si is formed on the surface. 相似文献
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A dispersion compensation method is introduced to correct the distorted image passing through an ultrathin metal film.An LCD-CCD system is modeled by the back propagation network and used to evaluate the transmittance of the ultrathin metal film.Training samples for the network come from 729 images captured by shooting test patches,in which the RGB values are uniformity distributed between 0 and 255.The RGB value of the original image that will be distorted by the dispersion is first transformed by mapping from the LCD to the CCD,multiplied by the inverse matrix of the transmittance matrix,and finally transformed by mapping from the CCD to the LCD,then the corrected image is obtained.In order to verify the effectiveness of the proposed method,ultrathin aluminum films with different thicknesses are evaporated on glass substrates and laid between the CCD and LCD.Experimental results show that the proposed method compensates for the dispersion successfully. 相似文献
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Optical Review - Both Fabry–Pérot interferometry and the DC electrochemical method have been simultaneously used for the first time to measure in situ the anodic current density (J) of... 相似文献
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Ultrathin graphene films find their use as advantageous support for nano- and biomaterials investigations. Thin film causes a very slight deterioration to measured signals, thus providing more details of the object's structure at nanoscale. The ultimate thinness of graphene works in the best way for this purpose. However, obtaining suspended thin film of a large-area, which is convenient for applications, is often a relatively complicated and time-consuming task. Here we present a one-step 1-min technique for synthesis of an extremely thin (about 1–2 nm) continuous film suspended over cells of a conventional copper grid (50–400 μm mesh). This technique enables us to acquire a large-area film which is water-resistant, stable in organic solvents and can act as a support when studying nanoparticles or biomaterials. Moreover, the very mechanism of the film formation can be interesting from the point of view of other applications of ultrathin graphene oxide papers. 相似文献
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Yoshida Y Schröder S Ferriani P Serrate D Kubetzka A von Bergmann K Heinze S Wiesendanger R 《Physical review letters》2012,108(8):087205
We report a transverse conical spin spiral as the magnetic ground state of a double-layer Mn on a W(110) surface. Using spin-polarized scanning tunneling microscopy, we find a long-range modulation along the [001] direction with a periodicity of 2.4 nm coexisting with a local row-wise antiferromagnetic contrast. First-principles calculations reveal a transverse conical spin-spiral ground state of this system which explains the observed magnetic contrast. The canting of the spins is induced by higher-order exchange interactions, while the spiraling along the [001] direction is due to frustrated Heisenberg exchange and Dzyaloshinskii-Moriya interaction. 相似文献
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The filtering properties for a narrowband reflection-and-transmission filter in an annular defective photonic crystal containing an ultrathin and strongly lossy metallic film are theoretically investigated based on the transfer matrix method for the cylindrical Bragg waves. At a certain design wavelength, simultaneous peaks in reflectance and transmittance can be found. The peak wavelength is shown to be dependent on the azimuthal mode number of the cylindrical waves. The peak heights in reflectance and transmittance can be directly varied by the stack numbers. In addition, the influence of the starting radius in reflectance and transmittance is also illustrated. 相似文献
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L. L. Afremov Yu. V. Kirienko A. A. Petrov 《Bulletin of the Russian Academy of Sciences: Physics》2014,78(2):104-107
The effect the thickness of an ultrathin film has on magnetic ordering is analyzed using the Ising model. It is shown that the dependence of the relative change in the Curie temperature on the thickness of an ultrathin film obeys a power law with an exponent equal to reverse critical exponent of spin-spin correlations ν = 0.69. The obtained results are in good agreement with the experimental data. 相似文献
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Optical Review - A novel method is proposed to measure the thickness of the indium tin oxide (ITO) film, which is less than 20 nm, using valid Fourier’s phase information of white... 相似文献
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Byoungseon Jeon Subramanian K.R.S. Sankaranarayanan Adri C.T. van Duin Shriram Ramanathan 《哲学杂志》2013,93(32):4073-4088
We investigate oxidation and oxide growth on single-crystal copper surfaces using reactive molecular dynamics simulation. The kinetics of surface oxide growth are strongly correlated with the microstructure of the metal substrates. Simulating oxide layer growth along the (100), (110), and (111) orientations of crystalline copper, oxidation characteristics are investigated at temperatures of 300?K and 600?K. The oxidation kinetics are found to strongly depend on the surface orientation, ambient temperature, and surface defects. The effect of surface morphology on oxidation characteristics is analyzed by comparing oxygen adsorption on various sites and the structure factor. The surface oxide formed on (100) retains the initial crystal structure in the 300–600?K range. The (100) surface shows the highest oxidation rate at both temperature conditions but saturates, facilitating oxygen adsorption on hollow sites. The oxidation kinetics of the (100) orientation are found to be not significantly affected by surface defects. (110) shows modest oxidation at 300?K but the highest oxidation is observed at 600?K. By surface disorder and reconstruction, the oxide layer is produced continuously. The (111) surface is sensitive to ambient temperature and surface defects, showing that surface reconstruction is a key element for further oxidation. The charge distribution of oxidized Cu atoms indicates multiple groups of stoichiometric oxides, while the fraction of CuO-like characteristics increases significantly on the (110) and (111) orientations at higher temperature (600?K). The energetics and mechanisms of oxidation on Cu metal substrates at the nanoscale are discussed in detail, and comparisons with available experimental and other theoretical studies are presented wherever possible. 相似文献
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《X射线光谱测定》2005,34(2):92-95
By using Monte Carlo simulation, the thickness of an aluminum oxide film in the nanometer range on aluminum sheets given different heat treatments was determined by electron probe microanalysis (EPMA) and compared with transmission electron microscopy (TEM). The film thickness was ≤50 nm. As a result, although the same analysis areas were not measured, similar deviations between EPMA and TEM were found. Consequently, we found that the Monte Carlo method was useful for measuring the oxide film thickness in the nanometer range on aluminum sheets. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
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A. V. Khomenko 《Technical Physics》2007,52(3):320-327
The melting of an ultrathin lubricant film at friction between atomically smooth surfaces is studied with allowance for fluctuations of its temperature, which are described by the Ornstein-Uhlenbeck process. The behavior of the most probable types of shear stresses arising in the lubricant is considered, and phase diagrams for second-and first-order phase transformations (the melting of an amorphous lubricant and that of a crystalline lubricant, respectively) are constructed. It is shown that, in the former case, lubricant temperature fluctuations lead to the formation of a stick-slip friction domain separating the domains of dry and sliding friction, which is typical of first-order transitions. In the latter case, three domains of stick-slip friction arise, which mark the transitions between dry friction and metastable and stable sliding friction. As the time of correlation of lubricant temperature fluctuations gets longer, the temperature of rubbing surfaces rises to the point where sliding friction sets in. 相似文献