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电沉积Co-Cu颗粒膜的巨磁电阻效应 总被引:4,自引:0,他引:4
从1988年Baibich首先在磁性Fe/Cr多层膜中发现巨磁电阻效应(GMR)以来 [1],由于GMR本身的科研价值和在磁记录、磁性传感器等方面的广泛应用前景 ,引起了人们的极大关注.继多层膜之后 ,人们在金属颗粒膜如Co Ag[2],Co Cu[3,4]等中也相继发现了巨磁电阻效应.颗粒膜是微颗粒镶嵌于薄膜中所构成的复合材料体系.原则上 ,颗粒的组成与薄膜的组成在制备条件上应互不固溶 ,因此颗粒膜区别于合金、化合物 ,属于非均匀相组成的材料.磁性颗粒膜是磁性粒子分布在非磁性金属材料薄膜中.在磁性颗粒与非… 相似文献
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半导体硅上电沉积Cu/Co层状薄膜 总被引:2,自引:0,他引:2
由磁性层和非磁性层组成的人工调制层状结构多层膜,其物性和磁性都表现出与其它结构的多层膜显著不同的特点,如巨磁阻效应[’,‘l、易磁性方向的改变等”].其性能的研究不但在磁性理论上具有重大意义,而且有望应用于高性能的磁阻敏感设备及提高磁记录密度等.因而近年来有关这方面的研究越来越引起人们的重视.目前,磁性多层膜的制备主要采用气相沉积、磁控溅射、分子束外延等真空技术.由于电沉积技术具有设备简单、操作方便等特点而成为制备多层膜的颇具活力的工艺.CO/Cll多层膜在C。层厚度较薄时具有较高室温巨磁阻(GMR)… 相似文献
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利用循环电位沉积法从非水体系中制备了Yb-Bi薄膜。在这一沉积过程中,基体电位是在两个电位之间连续循环的。研究了沉积电位、沉积时间和扫描速率对沉积膜中Yb含量以及表面形态的影响。实验结果表明,在0.10mol.L^-1Ybcl3 0.10mol.L^-1Bi(N03)3 0.10mol.L^-1LiCl DMSO体系中,当控制恰当的沉积条件,可得到表面黑色、均匀、有金属光泽和附着力强的非晶态Yb-Bi薄膜,其中Yb的质量分数可达21.04%~36.36%(质量分数),所得到的沉积膜通过SEM,EDS和XRD进行了表征。 相似文献
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酞菁及其衍生物等大环平面分子具有良好的化学稳定性和优异的光电性能 [1,2 ] ,利用酞菁进行模拟生物光合作用的研究 ,以期实现新的光电转换技术 ,近年来已引起人们的广泛重视[3~ 5] .分子沉积(MD)超薄膜[6~ 8] 是以阴阳离子间静电相互作用为成膜驱动力 ,通过相反离子体系的单层交替沉积制备的层状有序超薄膜 .分子沉积技术广泛应用在固体表面改性和生物传感技术等领域 ,沉积分子的物理化学性质是影响其应用的主要因素 .本文通过紫外 -可见光谱跟踪了酞菁铜阴阳离子 MD膜的均匀沉积 ,并根据酞菁 MD膜表面接触角的变化 ,探讨分子端基的… 相似文献
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利用循环电位沉积法从非水体系中制备了Yb-Bi薄膜。在这一沉积过程中,基体电位是在两个电位之间连续循环的。研究了沉积电位、沉积时间和扫描速率对沉积膜中Yb含量以及表面形态的影响。实验结果表明,在0.10mol.L^-1Ybcl3 0.10mol.L^-1Bi(N03)3 0.10mol.L^-1LiCl DMSO体系中,当控制恰当的沉积条件,可得到表面黑色、均匀、有金属光泽和附着力强的非晶态Yb-Bi薄膜,其中Yb的质量分数可达21.04%~36.36%(质量分数),所得到的沉积膜通过SEM,EDS和XRD进行了表征。 相似文献
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低温熔盐中电沉积Sm-Co合金膜及其磁性能 总被引:2,自引:0,他引:2
在353 K的尿素-乙酰胺-NaBr-KBr熔体中, 用恒电位电解法在Cu基片上制备了Sm-Co合金膜. 利用循环伏安法研究了熔体的电化学行为. 电化学实验结果表明, 在Pt电极上, Co(II)+2e→Co(0)是一步完全的不可逆反应; 测得CoCl2-尿素-乙酰胺-NaBr-KBr熔体中, Co(II)在Pt电极上的传递系数α=0.31, 扩散系数D0=4.78×10-5 cm2·s-1; Sm(III)难以单独沉积, 但能被Co(II)诱导共沉积, 在不同阴极电位下制备出不同Sm含量的非晶合金膜. 用等离子发射光谱仪(ICP)检测薄膜成分, 用SEM观察了薄膜的表面形貌结构, 用XRD和振动样品磁强计(VSM)分析样品退火前后的晶相和磁性能变化特征. 结果表明, 在923 K进行退火30 s后Sm-Co薄膜由非晶转变为多晶结构, 并以hcp晶相结构为主; 退火和Sm含量对Sm-Co合金膜的磁性能有重要的影响. 相似文献
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聚苯胺-TCNQ复合薄膜的微观结构与电学特性 总被引:3,自引:2,他引:1
聚苯胺 (PANI)作为高聚物材料 ,具有稳定性好 ,易于合成等优点.它在化学传感器、显示器、光化学电池等光电器件上有着许多潜在的应用前景.目前导电聚苯胺材料的合成、薄膜的制备与表征正在受到人们的重视.由于聚苯胺很难溶于一般的有机溶剂 ,用化学方法通过聚合物溶液用旋涂或自组装的方法成膜具有很大的局限性 ,特别是不易得到实用化的薄膜产物.而用真空蒸发沉积方法制备聚苯胺薄膜却有成膜质量高、易于控制 ,能很好与电子及微电子加工工艺相接轨等优点[1 -3].国外已有一些关于真空蒸发沉积聚苯胺薄膜的研究报导[2 -5],但… 相似文献
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Clemente-León M Coronado E Gómez-García CJ Mingotaud C Ravaine S Romualdo-Torres G Delhaès P 《Chemistry (Weinheim an der Bergstrasse, Germany)》2005,11(13):3979-3987
Langmuir and Langmuir-Blodgett (LB) films of a variety of polyoxometalates of different shapes, sizes, and charges were prepared by taking advantage of the adsorption properties of these polyanions on a positively charged monolayer of an organic surfactant spread on water. Three different aspects were investigated. 1) The electrochemical and electrochromic properties of LB films containing the easily reducible polyoxoanion [P2Mo18O62]6-. Absorbance changes of these LB films deposited onto an ITO substrate have been induced by repeated switching of the applied potential. These changes are due to the formation of the colored reduced forms of the polyanion. Coloration and bleaching of the LB film occur very quickly and are reversible. 2) The preparation of LB films based on magnetic polyoxometalates, such as the Keggin anions, [CoW12O40]6- and [SiMn(OH2)W11O39]6-, or containing magnetic clusters of increasing nuclearities such as [Co4(H2O)2(PW9O34)2]10- and [Co4(H2O)2(P2W15O62)2]16- based on a Co4O16 ferromagnetic cluster, and the polyoxometalates [Co9(OH)3(H2O)6(HPO4)2(PW9O34)3]16- and [Ni9(OH)3-(H2O)6(HPO4)2(PW9O34)3]16- based on a nonanuclear M9O36 cluster. 3) The preparation of LB films of the giant heteropolyoxomolybdate, [Na3(NH4)12][Mo57Fe6(NO)6O174(OH)3-(H2O)24]76 H2O. 相似文献
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Commercial polyimide films containing up to ~ 3 wt % water have been studied by proton, deuteron, and oxygen-17 nuclear magnetic resonance (NMR). Comparisons between NMR results and previous dielectric relaxation (DR) results for a variety of Kapton films show that there is a one-to-one correspondence between specific dielectric loss peaks and features of the 2H or 17O NMR spectra. It is concluded that water molecules, which interact only weakly with the polymer, reside in the polyimide matrix in two configurations, randomly oriented single molecules and chains of water molecules oriented perpendicular to the plane of the film. The correspondence between NMR and DR observed in water in Kapton extends to water in Upilex and to methanol and acetic acid in Kapton. © 1995 John Wiley & Sons, Inc. 相似文献
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Fabrication of photosensitive multilayer films based on polyoxometalate and diazoresin 总被引:1,自引:0,他引:1
A novel photosensitive organic-inorganic composite film incorporating polyoxometalate, K7[SiW11O39Co(H3P2O7)] (SiW11CoPP), and diazoresin (DR) has been prepared via layer-by-layer (LBL) self-assembly. Under UV irradiation, followed the decomposition of diazonium in DR, the ionic bonds between the adjacent interfaces of the multilayer film convert to covalent bonds. The LBL multilayers were characterized by UV-vis spectroscopy, X-ray photoelectron spectra (XPS), atomic force microscopy (AFM), FTIR spectrum, cyclic voltammograms (CV), and electron spin resonance (ESR) measurements. UV spectroscopy shows that the deposition process is regular and highly reproducible from layer to layer. XPS spectra confirm the incorporation of DR and SiW(11)CoPP into the films. Atomic force microscopy image indicates that the film surface is uniform and smooth. Solvent etching experiment proves that the film has significant stability towards polar solvent. Electrochemical behavior of the multilayers is investigated. 相似文献
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Chiral polyaniline composite (CPAC) thin films were fabricated by self-assembly using diazoresin (DR) and CPAC. The weak linkage between the DR and CPAC of the film will convert to covalent bonds under UV irradiation or heating, and the thin film becomes very stable toward polar solvents and electrolyte aqueous solutions. Core-shell particles with stable DR/CPAC shell and polystyrene (PS) core can be prepared by similar methods. After the PS core is removed by chemical etching, stable DR/CPAC hollow spheres were obtained. Circular dichroism spectra and cyclic voltammetry measurements show that the DR/CPAC thin films are chirally active and possess good electrochemical stability. 相似文献
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Mao-fengZhang Qiao-hongYao Chun-huiHuang Wei-xiaoCao 《高分子科学》2005,(1):27-27
A kind of azo-containing resin (Azo-R) was synthesized by a simple way through the coupling reaction of 2-nitro-N-methyldiphenylamine-4-diazoresin (NDR) with phenol, and a new covalentely attached multilayer film from Azo-R as H-donor and photosensitive diazoresin, diphenylamine-4-diazoresin (DR) as H-acceptor via H-bonding attraction by selfassembly technique has been fabricated. Following the decomposition of diazonium group of DR under exposure to UV light, the H-bonds between the layers of the film convert to covalent bonds and the film becomes very stable toward polar solvents or electrolyte aqueous solutions. Thus the UV-irradiated azo-containing films can be used to measure photocurrent in a conventional three-electrode photoelectrochemical cell using KCl as supporting electrolyte. It was confirmed that the azo-containing multilayer film is responsible for the photocurrent generation. 相似文献
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González Orive A Dip P Gimeno Y Díaz P Carro P Hernández Creus A Benítez G Schilardi PL Andrini L Requejo F Salvarezza RC 《Chemistry (Weinheim an der Bergstrasse, Germany)》2007,13(2):473-482
We have prepared ultrathin, nanostructured melanin films on Au(111) by means of electrochemical self-assembly. These films were characterized by using Auger electron spectroscopy, X-ray absorption near-edge structure spectroscopy, scanning tunneling microscopy, magnetic force microscopy, and electrochemical techniques. Two types of nanostructures are present in the film: melanin nanoparticles and Fe(3)O(4) nanoparticles. The melanin nanoparticles contain Fe bonded to oxygen-containing phenolic groups in an octahedral configuration similar to that found in Fe(2)O(3). The inorganic-organic composite exhibits magnetic properties and catalyzes the electroreduction of hydrogen peroxide in alkaline and neutral electrolyte solutions. The electrocatalytic activity depends on the Fe-bound melanin and appears to be similar to that found for Fe-porphyrins. 相似文献
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For the first time, cobalt oxide films that are highly protective against localized corrosion and depicting a wide variety of bright and uniform colors due to light interference, have been successfully electrogenerated on polycrystalline cobalt disk electrodes under potentiostatic polarization in a mild aqueous bicarbonate medium. Open circuit potential measurements have shown the formation of a film with a bilayered structure, organized as a thin Co3O4 outer layer and a thick CoO inner layer. The existence of Co3O4 as a thin outer layer, previously postulated from galvanostatic reduction experiments, has been confirmed from XPS analysis. Raman spectroscopy, performed using a very low laser intensity, has shown that the films are mainly composed of CoO. The broadness of the Raman bands observed is associated to the amorphous character of the film, a result that has been confirmed by spectroscopic ellipsometry and X-ray diffraction analysis. Overall film thicknesses, well controlled by the anodization duration, were determined and correlated using mechanical (atomic force microscopy and profilometry) and spectroscopic (specular UV-vis-NIR reflectance and ellipsometry) techniques. Spectroscopic ellipsometry, using a simple amorphous dispersion model, has proved efficient for measuring thicknesses of films ranging from 31 to 290 nm with very low standard deviations. The real part of the complex refractive indices of these films, ranging from 1.8 to 2.2 (at lambda = 632.8 nm) depending on the anodization duration, is in good agreement with values reported in the literature for CoO. The film with the highest refractive index, and consequently the more densely packed structure, was obtained following a 30-minute anodization period. 相似文献
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In this paper, the polyanion-containing cinnamoyl group (PACSS-CF3) was self-assembled with diazoresin (DR) to form a kind of stable covalent ultrathin film by irradiation with 365?nm UV light. The photoalignment properties of the DR/PACSS-CF3 covalent film were investigated. The covalent film was found to have anisotropy after irradiation by 297?nm linearly polarised ultraviolet light (LPUVL), and could induce uniform alignment of liquid crystals (LCs). The pretilt angle of the LC was 2.5°. The stability of the film was enhanced by the covalent bonds. The films were thermally stable to 180°C. Polarised UV-Vis spectroscopy was utilised to investigate the photochemical process of the covalent film. It was found that cinnamoyl moieties parallel to the polarisation direction of the LPUVL were consumed by the photoreaction faster than those perpendicular to the polarisation direction. It can be concluded that the selective photoreaction induced the anisotropy of the films. The anisotropic films induced the homogeneous alignment of LC. 相似文献
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Basova T Plyashkevich V Petraki F Peisert H Chassé T 《The Journal of chemical physics》2011,134(12):124703
The μ-(oxo)bis[phthalocyaninato] aluminum(III) (AlPc)(2)O films, with the crystallites oriented preferably in one direction, were obtained via chemical transformation of chloroaluminum(III) phthalocyanine AlClPc film upon its annealing in magnetic field. A comparative analysis of the influence of postdeposition annealing without and under applied magnetic field of 1 T on composition and morphology of AlClPc films has been carried out. The chemical transformation of AlClPc to (AlPc)(2)O on the substrate surface is studied by the methods of UV-vis and infrared spectroscopies, Raman, x-ray photoelectron spectroscopy as well as atomic force microscopy. Two interesting effects were observed upon heating the AlClPc films in magnetic field of 1 T. First, the temperature of the chemical transformation of AlClPc to (AlPc)(2)O decreased from 300 °C to 200 °C when magnetic field was applied during postdeposition annealing. Second, the formation of (AlPc)(2)O films with elongated crystallites with a preferential orientation was observed. The heating of (AlPc)(2)O films in a magnetic field at the same conditions did not demonstrate any effect on the structure and morphology of these films. 相似文献