共查询到20条相似文献,搜索用时 31 毫秒
1.
Fu-Der Lai Jui-Ming Hua C.Y. Huang L.A. Wang C.M. Chang Gia-Wei Chern 《Thin solid films》2006,496(2):247-252
Amorphous (ZrO2)x-(SiO2)1−x and (Al2O3)x-(ZrO2)y-(SiO2)1−x−y composite films were prepared using r.f. unbalanced magnetron sputtering in an atmosphere of argon and oxygen at room temperature. The (ZrO2)x-(SiO2)1−x and (Al2O3)x-(ZrO2)y-(SiO2)1−x−y composite films were completely oxidized when an O2/Ar flow rate ratio of 2.0 was used. The optical constants of these thin films depend linearly on the mole fraction of corresponding films. By tuning the (x, y) mole fractions of (Al2O3, ZrO2) in the (Al2O3)x-(ZrO2)y-(SiO2)1−x−y composite films, the optical constants can meet the optical requirements for a high transmittance attenuated phase shift mask (HT-AttPSM) blank. The n-k values in the quadrangular area in the (x, y) plane, where x and y represent the mole fractions of Al2O3 and ZrO2, respectively, meet the optical requirements for an HT-AttPSM blank with an optimized transmittance of 20 ± 5% in ArF lithography. It is noted that the quadrangular area is bounded by (0, 0.31), (0, 0.62), (0.26, 0) and (0.57, 0). All the films also met the chemical and adhesion requirements for an HT-AttPSM application. One (Al2O3)0.1-(ZrO2)0.52-(SiO2)0.38 composite film was fabricated with optical properties that meet the optimized optical requirements of ArF-line HT-AttPSM blanks. Combined with these HT-AttPSMs, ArF-line (immersion) lithography may have the potential of reaching 65-, 45-nm and possibly the 32-nm technology nodes for the next three generations. 相似文献
2.
In this study, we have demonstrated that boron doping of Ni-rich Li[NixCoyAl1−x−y]O2 dramatically alters the microstructure of the material. Li[Ni0.885Co0.1Al0.015]O2 is composed of large equiaxed primary particles, whereas a boron-doped Li[Ni0.878Co0.097Al0.015B0.01]O2 cathode consists of elongated particles that are highly oriented to produce a strong, crystallographic texture. Boron reduces the surface energy of the (0 0 3) planes, resulting in a preferential growth mode that maximizes the (0 0 3) facet. This microstructure modification greatly improves the cycling stability; the Li[Ni0.878Co0.097Al0.015B0.01]O2 cathode maintains a remarkable 83% of the initial capacity after 1000 cycles even when it is cycled at 100% depth of discharge. By contrast, the Li[Ni0.885Co0.1Al0.015]O2 cathode retains only 49% of its initial capacity. The superior cycling stability clearly indicates the importance of the particle microstructure (i.e., particle size, particle shape, and crystallographic orientation) in mitigating the abrupt internal strain caused by phase transitions in the deeply charged state, which occurs in all Ni-rich layered cathodes. Microstructure engineering by surface energy modification, when combined with protective coatings and composition modification, may provide a long-sought method of harnessing the high capacity of Ni-rich layered cathodes without sacrificing the cycling stability. 相似文献
3.
Z.Y. Nuru C.J. Arendse T.F.G. Muller M. Maaza 《Materials Science and Engineering: B》2012,177(14):1194-1199
We report on the microstructure and optical properties of AlxOy–Pt–AlxOy interference-type multilayer films, deposited by electron beam (e-beam) deposition onto corning 1737 glass, silicon (1 1 1) and copper substrates. The structural properties were investigated by Rutherford backscattering spectrometry, X-ray diffraction, scanning electron microscopy, energy dispersive X-ray spectroscopy and atomic force microscopy. The optical properties were extracted from specular reflection/transmission, diffuse reflectance and emissometer measurements. The stratification of the coatings consists of a semi-transparent middle Pt layer sandwiched between two layers of AlxOy. The top and bottom AlxOy layers were non-stoichiometric with no crystalline phases present. The Pt layer is in the fcc crystalline phase with a broad size distribution and spheroidal shape in and between the rims of AlxOy. The surface roughness of the stack was found to be comparable to the inter-particle distance. The optical calculations confirm a high solar absorptance of ∼0.94 and a low thermal emittance of ∼0.06 for the multilayer stack, which is attributed not only to the optimized nature of the multilayer interference stacks, but also to the specific surface morphology and texture of the coatings. These optical characteristics validate the spectral selectivity of the AlxOy–Pt–AlxOy interference-type multilayer stack for use in high temperature solar-thermal applications. 相似文献
4.
《Materials Letters》1988,6(7):208-210
Simple cubic perovskites derived from RBaO3 appear in the X-ray diagrams of materials with nominal composition R1−yNayBa2Cu3Ox with R = Ce, Pr, Tb. Y1−yBiyBa2Cu3Ox also contains this structure type. Materials are not superconducting at 77 K. The absence of YBa2Cu3Ox type structures in these cases is explained on thermodynamic arguments considering the high stability of phases R4+Ba2+O3 which dominate the phase diagram. 相似文献
5.
Ti3AlC2/Al2O3 nanopowders were synthesized by the combination of mechanically-induce self-propagating reaction (MSR) of Ti, C, Al and TiO2 powder mixtures and subsequently heat treatment. Effects of high energy milling and heat treatment temperatures on the phase transformation were investigated in detail. X-ray diffraction (XRD) was used to characterize the powders of milled and annealed, respectively. The morphology and microstructure of as fabricated products were also studied by scanning electron microscopy (SEM) equipped with energy-dispersive spectroscopy (EDS). Results show that TiC, TixAly and Al2O3 transitional phases were formed when the initial powder mixtures were milled for 24 h. The desired Ti3AlC2/Al2O3 nanopowders with high purity were obtained when annealed the as-milled powders at 1100 °C. SEM image confirmed that the as fabricated Ti3AlC2/Al2O3 particles has nanocrystalline layered structural matrix of Ti3AlC2, and the second phase of nanosized Al2O3 disperses uniformly in the Ti3AlC2 matrix. 相似文献
6.
Lead zirconate (PbZrO3 or PZ)-based antiferroelectric (AFE) materials, as a group of important electronic materials, have attracted increasing attention for their potential applications in high energy storage capacitors, micro-actuators, pyroelectric security sensors, cooling devices, and pulsed power generators and so on, because of their novel external electric field-induced phase switching behavior between AFE state and ferroelectric (FE) state. The performances of AFE materials are strongly dependent on the phase transformation process, which are mainly determined by the constitutions and the external field. For AFE thin/thick films, the electrical properties are also strongly dependent on their thickness, crystal orientation and the characteristics of electrode materials. Accordingly, various strategies have been employed to tailor the phase transformation behavior of AFE materials in order to improve their performances. Due to their relatively poor electrical strength (low breakdown fields), most PZ-based orthorhombic AFE ceramics are broken down before a critical switching field can be applied. As a consequence, the electric-field-induced transition between AFE and FE phase of only those AFE bulk ceramics, with compositions within tetragonal region near the AFE/FE morphotropic phase boundary (MPB), can be realized experimentally at room temperature. AFE materials with such compositions include (Pb,A)ZrO3 (A = Ba, Sr), (Pb1−3/2xLax)(Zr1−yTiy)O3 (PLZT x/(1−y)/y), (Pb0.97La0.02)(Zr,Sn,Ti)O3 (PLZST) and Pb0.99(Zr,Sn,Ti)0.98Nb0.02O3 (PNZST). As compared to bulk ceramics, AFE thin and thick films always display better electric-field endurance ability. Consequently, room temperature electric-field-induced AFE–FE phase transition could be observed in the AFE thin/thick films with orthorhombic structures. Moreover, AFE films are more easily integrated with silicon technologies. Therefore, AFE thin/thick films have been a subject of numerous researches. This review serves to summarize the recent progress of PZ-based AFE materials, focusing on the external field (electric field, hydrostatic pressure and temperature) dependences of the AFE–FE phase transition, with a specific attention to the performances of AFE films for various potential applications, such as high energy storage, electric field induced strains, pyroelectric effect and electrocaloric effect. 相似文献
7.
Chan -Soo Jee D. Nichols A. Kebede S. Rahman J. E. Crow A. M. Ponte Goncalves T. Mihalisin G. H. Myer I. Perez R. E. Salomon P. Schlottmann S. H. Bloom M. V. Kuric Y. S. Yao R. P. Guertin 《Journal of Superconductivity and Novel Magnetism》1988,1(1):63-80
The temperature and Zn concentration dependence of the electrical resistivity, specific heat, magnetic susceptibility, and electron paramagnetic resonance (EPR) spectra of YBa2(Cu1?x Zn x )3O7?y withy~0.1 has been measured forx≤0.16. In addition, the temperature and field dependence of the magnetization has been measured for 2<T<300K and 0<H<9.0T, along with the temperature and quasihydrostatic pressure dependence of the electrical resistivity for selected samples for 0<P<13 GPa. The substitution of Zn for Cu in YBa2Cu3O7?y causes a rapid and nearly linear depression of the superconducting transition temperature,T c , withT c going to 0 K forx≥ 0.10. YBa2(Cu1?x Zn x )3O7?y retains the YBa2Cu3O7-y orthorhombic structure forx≤0.16 for both the superconducting and nonsuperconducting samples. Initially, the unit cell volume increases nearly linearly with Zn content; however, an abrupt change occurs in the vicinityx=0.8–0.10. Forx<0.10, the temperature dependence of the electrical resistivity,ρ(T), is metallic-like (dρ/dT>0) andρ increases gradually with increasing Zn content. However, forx≥ 0.10,ρ(T) becomes semiconductor-like, with a very rapid increase of the resistivity with increasingx. The electrical resistivity, magnetic susceptibility, EPR spectra, and specific heat all indicate that thed-holes associated with the Cu ions become localized in the nonsuperconducting phase,x>-0.10. 相似文献
8.
L.G. Meiners 《Thin solid films》1984,113(2):85-92
Al2O3 and AlPxOy dielectric layers have been deposited on n-type InP substrates and the electrical properties of the interfaces have been evaluated by current-voltage and capacitance-voltage (C-V) measurements on metal- insulator-semiconductor diodes. Layers were deposited by combining trimethyl- aluminum, oxygen and phosphine in a low pressure chemical vapor deposition reactor in which the oxygen was excited in an r.f. plasma prior to mixing with the reactive gases in the deposition zone. The Al2O3 layers were invariably too conductive for meaningful C-V measurements; however, the AlPxOy layers not only were of high resistivity (? > 1016 Ω cm) but also exhibited interfacial properties superior to those of SiO2 layers on InP. The surface potential could be modulated over the full band gap of InP since the surface density was less than 1011 cm-2 eV-1 over much of the band gap. 相似文献
9.
The effect of Al2O3 content on the structure, electrical properties, magnetic properties, and interparticle exchange interactions of (Fe65Co35)1 − x(Al2O3)x films with Al2O3 volume fractions x ranging from 0 to 0.50 was systematically investigated. Among the films with x between 0 and 0.25, the lowest coercivity of 0.56 kA/m was achieved in the (Fe65Co35)0.82(Al2O3)0.18 film. This is ascribed to the strongest exchange interactions between the Fe65Co35 nanoparticles in this film. Combined with the microstructure analysis of the (Fe65Co35)1 − x(Al2O3)x films, the modified Herzer's model was extended to interpret the variation of the coercivity with x and analyze the effect of the exchange interactions between the Fe65Co35 nanoparticles on the magnetic softness. The remanence curves confirm the existence of the exchange interactions and reveal the evolution of the exchange interaction strength with Al2O3 content. 相似文献
10.
A. G. Belous O. V. Ovchar A. V. Kramarenko D. O. Mishchuk Bostjan Jancar Jana Bezjak Danilo Suvorov 《Inorganic Materials》2006,42(12):1369-1373
The formation of cobalt metaniobate, CoNb2O6, with the columbite structure has been studied, and possible ways of optimizing solid-state synthesis conditions have been examined. Single-phase CoNb2?y O6?2.5y has been obtained in the composition range 0 ≤ y ≤ 0.05. The microstructure and microwave dielectric properties of Co1?x Nb2O6?x materials have been investigated. The results indicate that the electrical Q of the nonstoichiometric materials drops sharply for x > 0 because of the presence of Nb2O5 as an impurity phase. For x < 0, Q gradually decreases with increasing Co content, which is caused by the rise in lattice strain and presence of Co4Nb2O9 impurity. 相似文献
11.
Geng Chang Xiao-hua Zhou Shu-ren Zhang Ting-ting Zhang Ying-xiang Li 《Journal of Materials Science: Materials in Electronics》2014,25(10):4439-4443
The effects of TiO2 and Al2O3 doping on the phase formation, the microstructure and microwave dielectric properties of Ba6?3x (Sm1?y ,Nd y )8+2x Ti18O54 (x = 2/3 and y = 0.5; BSNT) ceramics were investigated. X-ray diffraction patterns showed that the main crystal phase of BSNT + xTiO2 (x = 0–2) ceramics sintered at 1,280 and 1,300 °C for 5 h was Ba(Sm, Nd)2Ti4O12, accompanied by a small number of second phases: Ba2Ti9O20 and TiO2 (x ≥ 1.0), while the new phase BaAl2Ti5O14 appeared and the two phases Ba2Ti9O20 and TiO2 disappeared in BSNT ? 2TiO2 ceramic doped with ≥2 wt% Al2O3 successively as identified by scanning electron microscopy and energy dispersive spectroscopy analysis. The TiO2 and Al2O3 working as sintering aids conduced effectively to promote the densification and grain growth, and thus decreasing the sintering temperature, so when the amounts of TiO2 was increased, Q × f and τ f values increased continuously. The BSNT ? 2TiO2 ceramics doped with y wt% Al2O3 decreased the density and dielectric constant, increased the Q × f value remarkably and the τ f values was adjusted from 25.3 to ?7.3 ppm/ °C. When doped with 1.5 wt% Al2O3 sintered at 1,260 °C for 5 h, the ceramics obtained the excellent microwave dielectric properties: ε r = 74.3, Q × f = 11,928 GHz, and τ f = +5.39 ppm/ °C. 相似文献
12.
A. G. Afonin L. A. Alekseeva S. P. Borodai L. P. Lyashenko L. G. Shcherbakova E. I. Suzdal’tsev 《Inorganic Materials》2006,42(5):562-566
The phase composition of glass-ceramics produced by heat-treating lithium aluminosilicate glass at temperatures from 600 to 1300°C has been determined by x-ray diffraction and electron probe x-ray microanalysis. The materials heat-treated in the range 1000–1230°C have been shown to contain an Si0.65Al0.19Ti0.09Sb0.013Na0.032K0.013Ce0.008As0.013O1.864 glass phase and crystalline solid solutions: tetragonal spodumene-like Li1 ? 4x ? 2y TixZnyAlSi3O8 (x, y ≤ 0.05), sillimanite-based Al1.92Ti0.08SiO5.04, and rutile-based Ti0.99Sb0.01O2.005. The structures and lattice parameters of the crystalline phases have been determined. 相似文献
13.
《Materials Letters》2003,57(22-23):3427-3430
The magnetic parameters for single crystals of SrAlxFe12−xO19 (x=0, 0.8) were measured at 77 and 295 K. The nuclear magnetic resonance (NMR) experimental data of 57Fe nuclei in domains of these samples were determined in a wide range of temperatures using the spin-echo technique. Influence of substitution of Fe3+ ions by Al3+ ions on magnetic properties have been studied with the aid of NMR spectra of 57Fe nuclei. It is shown that only 82% of Al3+ exist in b-sublattice (site 2a) and 18% of Al3+ ions are statistically distributed in the other sublattices for SrAlxFe12−xO19. The percentage 82% Al3+ in sites 2a experimentally increases the value of anisotropy constant K1 by 0.60×106 erg cm−3. Thus, the contribution of Fe3+ ion in the position 2a to the magnetic anisotropy constant of SrFe12O19 in low temperatures is estimated. It is shown that the value K1(2a)=−0.90×106 erg cm−3. 相似文献
14.
The elastic properties of two series of lanthanum aluminosilicate glasses (15La2O3-xAl2O3-(85−x)SiO2 and 25La2O3-yAl2O3-(75−y)SiO2, where x, y=15, 20, 25, 30, 35 mol%), were obtained by the ultrasonic pulse-echo technique, at room temperature. The correlation of elastic stiffness, the cross-link density, and the fractal bond connectivity of these glasses are discussed. The derived experimental values of Young’s modulus, bulk modulus, shear modulus and Poisson’s ratio for our glasses are compared with those theoretically calculated values in terms of the Makishima-Mackenzie model. 相似文献
15.
The kinetics of finely divided, (Fe2+Fe3+2?xAl3+x)O4 type (0 ? x ? 2), substitution magnetites oxidation into metastable phase γ(Fe3+1?yAl3+y)2O3 (x = 3y) has been accounted for by means of the law of diffusion, under variable working conditions, of the cationic vacancies generated at solid-gas interface with a diffusion coefficient that decreases when the stoichiometric difference is high. The crystallites size and the trivalent substituant percentage increases, in both cases, slow down the reaction rate. 相似文献
16.
Lanthanum-modified lead zirconate titanate Pb1−xLax(Zr1−yTiy)O3 (PLZT) hollow nanospheres have been successfully prepared via a template-free hydrothermal method using the well-mixed coprecipitated precursors and the KOH mineralizer. The structure, composition, and morphology of the PLZT hollow nanospheres were characterized by XRD (X-ray diffraction), ICP (inductive coupled plasma emission spectrometer), FTIR (Fourier transform infrared spectra), TG/DTA (thermogravimetric analysis and differential thermal analysis), TEM (transmission electron microscopy) and SEAD (selected area diffraction). The results show that the composition and the morphology control of the PLZT products are determined by the KOH concentration. The PLZT hollow nanospheres with uniform size of about 4 nm were synthesized in the presence of 5 M KOH. The crystalline nanoparticles can be prepared at dilute KOH, in contrast to the amorphous powders prepared at concentrated KOH. Formation mechanisms of the PLZT hollow nanospheres are also discussed. 相似文献
17.
E. A. Filonova A. N. Demina E. A. Kleibaum L. Ya. Gavrilova A. N. Petrov 《Inorganic Materials》2006,42(4):443-447
We have revealed the formation of a continuous series of orthorhombic LaMn1 ? y FeyO3 solid solutions (0<y<1); La1 ? x SrxFeO3 solid solutions in the composition range 0 < x ≤ 0.8, with an orthorhombic structure at 0 < x ≤ 0.6 and a cubic structure at 0.6 < x ≤ 0.8; and a tetragonal SrMn1 ? y FeyO3 phase in the range 0.6 ≤ y ≤ 1. The composition stability limits of the perovskite phase La1 ? x SrxMn1 ? y FeyO3 have been determined, and the 1100°C isotherm of the La2O3-SrO-Mn3O4-Fe2O3 system in air has been constructed. 相似文献
18.
The electrical resistivity of several types of (V1?x?yMxM′y)2O3 alloys have been investigated, where M and M′ represent Al, Ga, and 3d transition metal elements. It was found that effects previously obtained by incorporation of M = Al, Cr, may be counteracted by use of M′ = Ti or Ga. On the basis of this information 3-dimensional phase diagrams have been sketched out; several sets of critical points have been encountered. The physical characteristics of (Ti1?yCry)2O3 have also been determined; the electrical properties of the alloy y = 0.4 and 0.6 are remarkably similar to those of (V1?xCrx)2O3 with x = 0.02, 0.03. 相似文献
19.
G. Raina 《Materials Research Bulletin》2004,39(9):1271-1277
Nitrides such as Si3N4 and GaN are made by the reaction of the respective oxide with N2 or NH3. In order to understand the mechanism of formation of nitrides, reactive laser ablation of B2O3, Al2O3, Ga2O3, and SiO2 in pure form, as well as in mixture with carbon, has been carried out in an atmosphere of nitrogen or ammonia in a pulsed supersonic jet. The reaction of N2 with SiO2 gives nitridic species such as Si2Ny (y≤5) in the vapor phase. On reaction with N2 in the presence of carbon, B2O3 and Ga2O3 yield species of the type BxNy and GaNy, respectively. Nitridic species are preponderant in the reaction with ammonia only in the case of SiO2. Al2O3 predominantly gives oxynitridic species under the reaction conditions examined. 相似文献
20.
N. P. Bansal 《Journal of Materials Science》1993,28(9):2433-2437
Eleven different compositions in the system YBa2(Cu3–x
Al
x
Oy(x=0-0.3) have been synthesized and characterized by electrical resistivity measurements, powder X-ray diffraction, and scanning electron microscopy. The superconducting transition temperature,T
c (onset), was almost unaffected by the presence of alumina due to its limited solubility in YBa2Cu3O7–x
. However,T
c(R=0) gradually decreased and the resistive tails became longer with increasing Al2O3 concentration. This was probably due to formation of BaAl2O4 and other impurity phases from chemical decomposition of the superconducting phase by reaction with Al2O3. 相似文献