Field-driven creep motion of a composite domain wall in a Pt/Co/Pt/Co/Pt multilayer wire

We have studied the field-driven motion of a pair of coupled Bloch domain walls in a perpendicular magnetic anisotropy Pt/Co/Pt/Co/Pt multilayer Hall bar. The nucleation of an isolated but coincident pair of walls in the two Co layers, observed by Kerr microscopy, took place at an artificial nucleation site created by Ga⁺ ion irradiation. The average velocity v of the wall motion was calculated from time-resolved magnetotransport measurements at fixed driving field H, where the influence of the extraordinary Hall effect leads to the observation of voltages at the longitudinal resistance probes. We observed a good fit to the scaling relation lnv∝H^−1/4, consistent the motion of a single 1-dimensional wall moving in a 2-dimensional disordered medium in the creep regime: the two walls are coupled together into a 1-dimensional composite object.     

High frequency characteristics of NiO/(FeCo/NiO)10 multilayers with exchange anisotropy

[NiO/Fe₆₅Co₃₅]₁₀ exchange-coupled multilayer films for high frequency applications are fabricated, and their static magnetic property and microwave permeability are studied systematically. Both exchange bias field and ferromagnetic resonance frequency of the multilayers increase with decreasing Fe₆₅Co₃₅ thickness, which means that the microwave properties such as permeability and FMR frequency can be controlled by changing Fe₆₅Co₃₅ thickness in the exchange-coupled films. Ferromagnetic resonance frequencies beyond 7 GHz of the films are measured and reported for the first time.     

Effects of thermal annealing on structural and magnetic properties of thin Pt/Cr/Co multilayers

Thermal stability of thin Pt/Cr/Co multilayers and the subsequent changes in their structural, magnetic, and magneto-optical properties are reported. We observe CoCrPt ternary alloy phase formation due to annealing at temperatures about 773 K, which is accompanied by enhancement in the coercivity value. In addition, 360° domain wall superimposed on a monodomain like background has been observed in the pristine multilayer, which changes into a multidomain upon annealing at 873 K.     

Improving mechanical properties of a-CNx films by Ti-TiN/CNx gradient multilayer

Amorphous carbon nitride (a-CN_x) films with functional gradient Ti-TiN/CN_x underlayer were deposited by direct current magnetron sputtering. Microstructure and composition of the films were characterized by means of X-ray diffraction (XRD), Raman spectroscopy, atomic force microscope (AFM) and transmission electron microscopy (TEM). Mechanical and tribological properties were investigated by nanoindenter, scratch and ball-on-disk tribometer. The a-CN_x-based films suffer a graphitization process with the increasing deposition temperature, thus the hardness and elastic modulus decrease. With the design of the Ti-TiN/CN_x gradient underlayers, some important advantages of relatively thick CN_x films can be achieved, such as increased hardness, improved adhesion strength, and the wear resistance of the a-CN_x-based films can be also improved significantly.     

Long‐time stability and asymptotic analysis of the IFE method for the multilayer porous wall model

In this article, we study the long‐time stability and asymptotic behavior of the immersed finite element (IFE) method for the multilayer porous wall model for the drug‐eluting stents. First, with the IFE method for the spatial descretization, and the implicit Euler scheme for the temporal discretization, respectively, we deduce the global stability of fully discrete solution. Then, we investigate the asymptotic behavior of the discrete scheme which reveals that the multilayer porous wall model converges to the corresponding elliptic equation if approaches to a steady‐state in both and norms as . Finally, some numerical experiments are given to verify the theoretical predictions.     

供需模型在众包平台定价中的应用

以众包平台为对象,基于已有数据,考虑供求关系,通过因子分析法对原始数据加以处理,建立任务的定价模型.在实际应用中,可以对分布密集的任务进行打包,并给出针对这种情况的定价模型.结果表明:提出的模型不仅考虑了会员人数与任务数量的关系,还考虑了个人需求的差异,提高了任务的完成度,对众包平台定价的发展与完善有着重要的意义.     

Improving attosecond pulse reflection by large angle incidence for a periodic multilayer mirror in the extreme ultraviolet region

The improvement of attosecond pulse reflection by large angle incidence for a periodic multilayer mirror in the extreme ultraviolet region has been discussed. Numerical simulations of both spectral and temporal reflection characteristics of periodic multilayer mirrors under various incident angles have been analyzed and compared. It was found that the periodic multilayer mirror under a larger incidence angle can provide not only higher integrated reflectivity but also a broader reflection band with negligible dispersion, making it possible to obtain better a reflected pulse that has a higher pulse reflection efficiency and shorter pulse duration for attosecond pulse reflection. In addition, by increasing the incident angle, the promotion of attosecond pulse reflection capability has been proven for periodic multilayer mirrors with arbitrary layers.     

Microstructure and properties of Nb/Ta multilayer films irradiated by a high current pulse electron beam

Nb/Ta multilayer films deposited on Ti6Al4V substrate with Nb and Ta monolayer thicknesses of 30 nm, 120 nm, and 240 nm were irradiated by a high current pulse electron beam (HCPEB) to prepare Nb-Ta alloyed layers. The microstructure and the composition of the outmost surface of melted alloyed layers were investigated using a transmission electron microscope (TEM) equipped with an X-ray energy dispersive spectrometer (EDS) attachment. The Ta content of the alloyed surface layer prepared from the monolayer of thickness 30 nm, 120 nm, and 240 nm was ～ 27.7 at.%, 6.37 at.%, and 0 at.%, respectively. It was found that the Ta content in the alloyed layer plays a dominant role in the microstructure of the films. The hardness and the wear rate of the alloyed layers decrease with the increasing content of Ta in the surface layer.     

Visible Channeled Spectra of a Multilayer Wood Filter

The transmission factor of multilayer Wood filters containing quartz and rutile layers was simulated in order to avoid the experimental trials for obtaining optical filters with predicted transmission. The main refractive indices of uniaxial crystals—quartz and rutile—were interferometrically determined and Cauchy constants were obtained by simulation. The transmission factor of optical devices consisting of quartz and rutile layers was simulated using the Maple Program.