Showing papers on "Texture (crystalline) published in 1991"
TL;DR: In this article, a single-phase tetragonal zirconium oxides have been made by the incorporation of 5.4 mol-% of Y3+ or La3+ in ZrO2 to form solid solutions.
142 citations
TL;DR: The bombardment of a growing film with energetic particles has been observed to produce beneficial modifications in a number of characteristics and properties critical to the performance of thin films and coatings such as: improved adhesion; densification of films grown at low substrate temperatures; modification of residual stresses; control of texture (orientation); modification of grain size and morphology; modifications of optical properties; and modification of hardness and ductility as mentioned in this paper.
133 citations
TL;DR: In this paper, texture analysis of aluminum films was performed at three different conditions, such that texture is the only microstructural variable, and it was shown that random and (111) fiber texture components are present in the films deposited by both partially ionized beam (PIB), physical vapor deposition and sputtering.
Abstract: Aluminum films deposited at three different conditions, such that texture is the only microstructural variable, were tested for electromigration behavior. Texture analysis shows that random and (111) fiber texture components are present in the films deposited by both partially ionized beam (PIB), physical vapor deposition and sputtering. Two parameters are required to properly quantify the texture: (111) volume fraction and the distribution (half‐width) of the (111) fiber component. As the (111) texture becomes stronger, the median time to failure increases, while the failure standard deviation decreases. Previous texture correlations are based on incomplete information, so they cannot predict electromigration behavior in all cases.
129 citations
TL;DR: In this paper, the authors showed that Ni−10% and 10% Cu alloys can only be deposited from a single electrolyte if the preferred orientation for the two metals is the same.
Abstract: As the layer thicknesses in 90% Ni‐10% Cu multilayered alloys electrodeposited from a sulfamate bath are decreased, the ultimate tensile strength peaks at 1100 MPa for 6–7 nm Cu layers, and then decreases to about 1000 MPa as the Cu layer thickness reaches 1 nm. This decrease in deposit strength is associated with a reduction in the deposit (100) texture caused by the influence of Cu, which has a (110) preferred orientation in the sulfamate system. The results suggest that highly coherent nanostructured multilayers can only be deposited from a single electrolyte if the preferred orientation for the two metals is the same.
110 citations
TL;DR: A technique to surface-texture polymer sheets with any conceivable surface morphology that allows the definition and control of implant surface texture at subcellular levels, down to 2 micron dimensions, and the cellular response to those textures to be studied in vitro and in vivo is described.
106 citations
TL;DR: In this article, the dielectric properties of grain-oriented thin-film vanadium dioxide (VO2) on single-crystal sapphire have been measured as a function of temperature across the phase transformation at 68 °C.
Abstract: The dielectric properties of grain‐oriented thin‐film vanadium dioxide (VO2) on single‐crystal sapphire have been measured as a function of temperature across the phase transformation at 68 °C. The properties of the low‐ and high‐temperature phases were determined by measuring the millimeter‐wave transmittance and phase shift through the samples. The real part of the dielectric constant in the high‐temperature phase increases with increasing thickness from less than 1000 for a 40‐nm‐thick film (the resolvable limit of this measurement technique) to over 90 000 for a 580‐nm‐thick film. The strong thickness dependence in epitaxial VO2 thin films can be attributed to a dielectric mixture phenomenon and can be described by effective‐medium theory. The large real dielectric constant and its thickness dependence is likely due to bonding distortions at the grain boundaries. Analysis of the experimental data shows the VO2 thin films used in this study have no secondary grain‐boundary phases, but do have interfacial stresses which affect the dielectric properties of the grain‐boundary regions that lie near the VO2‐sapphire interface. This study concludes that the millimeter‐wave properties of VO2 thin films are strongly influenced by microstructure, crystalline orientation, grain‐boundary stress, and stoichiometry.
100 citations
TL;DR: In this paper, a hierarchical plasminarity model was proposed for the quartz-water system, in which grain boundaries consist of islands capped by grain-boundary films, separated by microcapillaries, and connected to intergranular porosity.
Abstract: Data on dissolution, diffusion, and growth in the quartz-water system show that diffusion through grain-boundary films is rate limiting for solution transfer and too slow to permit significant compaction in geologic time, but that rates are more reasonable if the rough texture of natural grain boundaries is considered. On the basis of scanning electron microscope observations, a model is proposed that uses a hierarchical plumbing system in which grain boundaries consist of islands capped by grain-boundary films, separated by microcapillaries, and connected to intergranular porosity. A rate law based on such a model has an inverse grain-size dependence up to a critical grain size that is large (>>10 cm) under typical compaction conditions.
86 citations
01 Jan 1991
TL;DR: In this article, the evolution of two commonly observed polycrystalline morphologies, which give rise to textures, was described as well as the development of four films grown to produce,, and near '' textures with various combinations of growth facets.
Abstract: The textures, surface morphologies, structural perfection, and properties of diamond films grown by activated chemical vapor deposition (CVD) vary greatly with the growth conditions. The evolution of two commonly observed polycrystalline morphologies, which give rise to textures, will be described as well as the development of four films grown to produce , , and near '' textures with various combinations of growth facets. These films were grown to test models of texture development. Films free of twins, microtwins, and stacking faults are deposited when only (100) facets are permitted to grow. In polycrystalline materials, special conditions must be met to avoid the formation of planar defects at the peripheries of individual crystallites. The planar defects grow from (111) or mixed microfaceted surfaces. Twinning plays an important role in growth of (111) faceted surfaces. The films have been characterized with Raman spectroscopy, x-ray diffraction, transmission electron microscopy (TEM), scanning electron microscopy (SEM), and optical methods. 13 refs., 7 figs.
77 citations
TL;DR: In this article, BaSnO3 has been used to improve the magnetization properties of YBa2Cu3O6+x/Y2BaCuO5 composite wires.
Abstract: Additions of BaSnO3 have been made to YBa2Cu3O6+x/Y2BaCuO5 composite wires to examine its potential for improving solidification processing and enhancing pinning. Zone melting has been used to produce texture in extruded YBa2Cu3O6+x (Y‐123) wires with Y2BaCuO5(211) and BaSnO3 additions. BaSnO3 additions markedly improve the magnetization properties over similarly textured Y‐123 or Y‐123+211 wires in low fields, but do not show a noticeable improvement at higher fields (≳2 T). Microstructural effects of BaSnO3 include the growth of much larger Y‐123 grains, and a substantial reduction in size of 211 precipitates. Magnetic critical current densities (Jc) in excess of 1.2×105 A/cm2 in zero field, and 3.0×104 A/cm2 at 1 T are observed.
70 citations
TL;DR: In this article, the effect of Cr orientation on the crystallographic orientation of Co-based thin films was investigated using four experimental techniques: X-ray diffraction, selected area (electron) diffraction (SAD), electron microdiffraction, and atomic resolution electron microscopy of cross sections of the bi-layer films.
Abstract: Some of the evidence for the effect of Cr orientation on the crystallographic orientation of Co-based thin films is presented. The authors review four experimental techniques that can be used to investigate the orientation relationships (OR) between the magnetic Co-based film and the Cr underlayer. These techniques are X-ray diffraction, selected area (electron) diffraction (SAD), electron microdiffraction, and atomic resolution electron microscopy of cross sections of the bi-layer films. The authors focus on the crystallographic orientation relationships between the grains in the magnetic film and those in the Cr (BCC) underlayer. The magnetic films discussed are all alloys of Co, usually with HCP structure. >
69 citations
TL;DR: In this paper, electron diffraction and microscopy were applied to study the domain structure of Y-Ba 2 Cu 3 O 7−δ single crystals, which revealed a finer "tweed" structure of overlapping lenticular domains oriented along [120] and [1 1 0].
Abstract: Fe-doped YBa 2 Cu 3 O 7−δ single crystals have been prepared by a flux method from an Y-Ba-Cu-O precursor with copper partially substituted by iron. Electron diffraction and microscopy were applied to study the domain structure of the material. Superposed on a broad twin band texture, as also observed in undoped material, all samples reveal a finer “tweed” structure of overlapping lenticular domains oriented along [120] and [1 1 0]. This suggests a two-step formation process of the domain structure. The displacement field, corresponding with the tweed structure, resembles that of microtwinning in undoped, quenched YBa 2 Cu7 3 O 7−δ samples. The randomly dispersed Fe-ions act as pinning centers or fragment the structure by the induction of twin interfaces. Monte Carlo simulations support this idea.
Abstract: In order to produce thin media with high intrinsic coercivity, we studied a number of CoSm films produced by rf‐diode sputtering. We determined an optimized set of sputtering parameters for films sputtered both on glass and NiP‐coated Al substrates with and without Cr underlayers. While the coercivity of the films depended strongly on argon pressure, the 〈110〉 texture of the Cr underlayer remained unaffected by it. The 〈110〉 texture of Cr changed to 〈200〉 texture at temperatures ≥300 °C, and the coercivity of the film was significantly reduced. Under optimal conditions we obtained intrinsic coercivities ≳2400 Oe for films with thickness <20 nm.
TL;DR: When a cross of either static or moving texture is inserted in the intersection of an Ehrenstein figure, it is found that the texture and its motion appear to spread outside of the cross, analogous to neon color spreading.
Abstract: When a cross of either static or moving texture is inserted in the intersection of an Ehrenstein figure, we find that the texture and its motion appear to spread outside of the cross. We suggest that these phenomena are analogous to neon color spreading, wherein an interpretation of a transparent surface makes the properties of that surface, which are physically visible only inside the cross, appear to spread over its apparent extent. In our experiments, the texture and the motion of the cross are attributed to the transparent surface. In addition, the spreading changes the apparent aperture within which the texture and its motion are seen, leading to a corresponding change in the apparent direction of motion.
TL;DR: In this paper, the authors investigated the texture which appears as parallel stripes perpendicular to the smectic layers in SSFLC cells and found that the width of the stripes is approximately equal to the thickness of the cell and presented a theoretical explanation of the equivalence.
Abstract: We investigate the texture which appears as parallel stripes perpendicular to the smectic layers in SSFLC cells When the temperature approaches the smectic A to smectic C* transition from above in the smectic A phase, a DC field induces the chevron structure due to the electroclinic effect and then the stripe texture is formed We have identified the stripes to be parallel zig-zag walls We show that a reasonably high DC voltage changes the structure of the cell from chevron to book-shelf in the smectic C* phase and we show how this happens We have experimentally found that the width of the stripes is approximately equal to the thickness of the cell and we present a theoretical explanation of the equivalence We have measured the layer tilt angles in the plane of the cell as a function of temperature and have found them to be the same as the chevron tilt angles determined by X-ray scattering The result confirms the chevron layer structure and stripe texture models and also gives a simple way t
TL;DR: Binary SmFe12 and Sm(Fe,T)12 films, where T =Ti and V, crystallized into the ThMn12-type structure, have been synthesized as sputtered films such that the c axes of the crystallites are oriented perpendicular to the film plane as discussed by the authors.
Abstract: Binary SmFe12 and Sm(Fe,T)12 films, where T =Ti and V, crystallized into the ThMn12‐type structure, have been synthesized as sputtered films such that the c axes of the crystallites are oriented perpendicular to the film plane. It has been possible to synthesize Sm(Fe,T)12 films which exhibit a very dominant (002) texture with intrinsic coercivities of 5 or more kOe. Such films exhibit flux densities 4πMs of more than 10 kG perpendicular to the film plane. No discernible columnar structure is exhibited so that the static energy product measured perpendicular to the film plane is nearly 21 MGOe.
TL;DR: The microstructure and magnetic properties of CoPtCr thin films with restricted fiber texture were characterized and subsequently correlated with the domain configuration during the magnetization reversal process as mentioned in this paper, which exhibited a bicrystal mode associated with two orthogonal easy axes of magnetization in the plane of the film.
Abstract: The microstructure and magnetic properties of CoPtCr thin films with 〈1120〉 restricted fiber texture grown on (100) planes of Cr single‐crystal films were characterized and subsequently correlated with the domain configuration during the magnetization reversal process. These films exhibited a bicrystal mode associated with two orthogonal easy axes of magnetization in the plane of the film. The domain configuration of these films during the magnetization‐reversal process consisted of two sets of domains extending in two orthogonal directions. These properties were compared with those of CoPtCr films with random crystallographic orientation.
TL;DR: In this article, Li doping has not changed the films c-axis preferential orientation typical of the undoped ZnO films, but it introduces a crystallite order change, as is expected by deposition of doped oxides the sputtering gas mixture is the main parameter controlling the dopant concentration.
Abstract: ZnO:Li films have been prepared by radio frequency (rf) diode sputtering using a Li‐doped ZnO target. The film depositions were performed in pure Ar or in 28% O2/Ar sputtering gas. For comparison undoped ZnO films were also prepared. Structural, electrical, and optical measurements have been performed on films prepared under different deposition conditions and the results related with Li content and O/Zn ratio obtained by nuclear reaction and Rutherford backscattering measurements, respectively. The Li doping has not changed the films c‐axis preferential orientation typical of the undoped films, but it introduces a crystallite order change. As is expected by deposition of doped oxides the sputtering gas mixture is the main parameter controlling the dopant concentration. Moreover, the oxygen presence in gas mixture has also been found to play an important role in controlling the optical properties of the film. The change in lithium concentration does not affect the electrical resistivity if the deposition ...
TL;DR: In this article, a powder-in-tube (Pb-doped bismuth-based 2223 powder was initially prepared then packed into silver tubes using a combination of cold work and heat treatment.
Abstract: Using a ‘‘powder‐in‐tube’’ process long lengths of high Tc prototype tape have been fabricated with high critical currents at liquid‐nitrogen temperature and excellent high field properties at liquid‐helium temperature. A Pb‐doped bismuth‐based 2223 powder was initially prepared then packed into silver tubes. Using a combination of cold work and heat treatment, a high degree of texture and good compaction with uniform properties was achieved. Current densities exceeding 10 000 A/cm2 at 77 K and 50 000 A/cm2 at 4.2 K in zero field were measured. At the 4.2 K temperature, the material still carried approximately 14 000 A/cm2 at 8 T. Tests on spirally wound and reacted coils, 52 cm long, have also demonstrated high current carrying capability. Effects of process variations and observed microstructure on superconducting properties are described.
01 Jul 1991-Nuclear Instruments & Methods in Physics Research Section B-beam Interactions With Materials and Atoms
TL;DR: In this article, the influence of ion bombardment during deposition of thin films and coatings (IBAD) on their mechanical and chemical behaviour is reviewed in order to define the present status of IBAD techniques compared with other PVD processes.
Abstract: Directed energy in the form of energetic ion beams is an excellent tool for the modification of thin film and interface properties. The easy control of ion beam parameters causes the high flexibility of the technique. The influence of ion bombardment during deposition of thin films and coatings (IBAD) on their mechanical and chemical behaviour is reviewed in this article. Firstly the controlled production of IBAD films or multilayers with well defined composition is described. Secondly the influence of ion bombardment on selected properties is considered. Adhesion, stress and structure or texture and their dependence on process parameters are discussed. Thirdly the role of adhesion, stress and porosity of films for their use for corrosion and oxidation protection is treated. Finally in the conclusion an attempt is made to define the present status of IBAD techniques compared with other PVD processes.
Patent•
06 May 1991
TL;DR: In this paper, a multi-layer friction element consisting of carbon-carbon composite material comprising a structure layer of coarse texture comprising segments of rovings and at least one friction layer of fine texture comprising fibre segments is presented.
Abstract: A multi-layer friction element is disclosed consisting of carbon-carbon composite material comprising a structure layer of so-called "coarse" texture comprising segments of rovings and at least one friction layer of so-called "fine" texture comprising fibre segments. A method also is disclosed for producing the friction element by preparation of a fibrous substrate by introducing segments of roving and/or fibers into a mould preferably by means of a distribution apparatus. Further disclosed is an apparatus for automatically obtaining a fibrous substrate of predetermined texture.
TL;DR: BaTiO3 thin films were prepared on MgO(100) substrates by chemical vapor deposition using barium β-diketonate {Ba(C11H19O2)2} and titanium tetraisopropoxide {Ti[OCH(CH3)2]4} as metal precursors as mentioned in this paper.
Abstract: BaTiO3 thin films were prepared on MgO(100) substrates by chemical vapor deposition using barium β-diketonate {Ba(C11H19O2)2} and titanium tetraisopropoxide {Ti[OCH(CH3)2]4} as metalorganic precursors. BaTiO3 films deposited at 800-1000°C showed prominent a-axis orientation perpendicular to the substrate surface. The deposition rate of these films was 1.0-1.2 µm/h. The rocking curve of BaTiO3(200) reflection from the film deposited at 800°C indicated strong crystallographic orientation. The epitaxial relationship between the film and the substrate was found by X-ray pole figure analysis. The relative dielectric constant of a polycrystalline BaTiO3 film prepared on a Pt(100)/MgO(100) substrate at 800°C was 1040 (10 kHz, 20 V/cm).
TL;DR: In this article, a single crystal growth was investigated by depositing thin films at various growth conditions and on several different orientations of rutile titania and sapphire single crystal substrates.
Abstract: Tin oxide films were deposited by organometallic chemical vapor deposition using tetramethyltin and oxygen as reactants Possibilities for single crystal growth were investigated by depositing thin films at various growth conditions and on several different orientations of rutile titania and sapphire single crystal substrates Single crystal films were deposited on titania (110) oriented crystals The morphology of these films appears practically featureless at 40 kx in a scanning electron microscope Atomic resolution images of these films were also obtained using atomic force microscopy Highly textured polycrystalline films were grown on rutile titania (100), (001), and (111) oriented single crystals X‐ray diffraction results show that the orientation of these films follows that of the substrate Single crystal films having a submicron sized morphology were deposited on sapphire (1102) crystals Films grown on sapphire (0001) substrates are polycrystalline and show strong (200) or (110) texture depen
TL;DR: In this paper, the authors report on CoNiCr thin films that were sputtered onto (100 and (110) Cr single crystals as well as polycrystalline Cr TEM folls.
Abstract: This paper reports on Co{sub 62.5} Ni{sub 30}Cr{sub 7.5} thin films that were sputtered onto (100) and (110) Cr single crystals as well as polycrystalline Cr TEM folls. VSM measurements have revealed the existence of an anisotropy in the in-plane coercivity. This stems from the development of a crystallographic texture in the plane of the film. TEM investigations have found the presence of crystallographic variants in the direction of the hcp c-axis in the CoNiCr films deposited on (100) and (110) Cr surfaces. Lorentz microscopy studies have found relatively straight domain walls which lie parallel to the specific crystallographic directions. The direction of magnetization within each domain is along the c-axis.
TL;DR: In this paper, the spherulitic texture of a polyethylene oxide (PEO) mixture has been examined and morphological observations of spherular textures of a PEO mixture containing low and high-molecular mass components at different supercooling and cooling rates have been delat with.
Abstract: Two somewhat separate issues have been delat with: the diffusion coefficients of various poly(ethylene oxide) (PEO) fractions at different temperatures; and morphological observations of spherulitic textures of a PEO mixture containing low- and high-molecular mass components at different supercooling and cooling rates. We found that simultaneous knowledge of diffusion coefficient of PEO fractions and crystal growth rate of the mixture leads to a better description of the crystal growth. As observed, the spherulitic texture of the PEO mixture comprises three texture levels: the spherulite as a whole; the crystalgrowth unit comprised of different number of lamellae in a stack; and the individual lamellar crystal. Under certain crystallization conditions, the thickness of the lamellar stack is on the same order of magnitude as the parameter δ proposed by Keith and Padden.
TL;DR: In this article, polycrystalline thin films of Cd1-xZnxTe on glass were grown by pulsed laser deposition using an XeCl excimer laser.
TL;DR: In this article, the texture analysis of the nickel deposits was realized by X-ray diffractometry and the surface morphology was studied by scanning electron microscopy techniques, and it was observed that variation of the reversed current parameters results in a total modification of the texture and surface morphology of the deposited metal.
Abstract: The reversed current (RC) technique perturbs the nickel electrocrystallization process by modification of the adsorption-desorption phenomena occuring on the cathodic area and causes a radical change of the structural characteristics and properties of the deposits. The purpose of this work is to study the modifications occurring in the crystalline orientation and surface morphology of nickel deposits, prepared from an organic-free Watts bath, by application of the RC technique. The texture analysis of the deposits was realized by X-ray diffractometry and the surface morphology was studied by scanning electron microscopy techniques. It was observed that variation of the RC parameters results in a total modification of the texture and surface morphology of the deposited metal. The roughness of the metallic surface was also examined and conditions for the preparation of bright and smooth deposits were determined.
TL;DR: Using submerged jet electropolishing, extremely thin, continuous, thermal oxide "windows" have been prepared on polycrystalline titanium (Ti), allowing a systematic investigation of the structure of thermal surface oxide layers on Ti in the thickness range 6-40 nm, corresponding to oxidation temperatures 100-450 degrees C.
Abstract: Using submerged jet electropolishing, extremely thin (less than 10 nm), continuous, thermal oxide "windows" have been prepared on polycrystalline titanium (Ti). The preparation technique is described in detail. It has allowed a systematic investigation of the structure of thermal surface oxide layers on Ti in the thickness range 6-40 nm, corresponding to oxidation temperatures 100-450 degrees C. Auger electron spectroscopy was used for oxide characterization and for depth profiling to determine oxide thickness. The thinnest oxides, less than 10 nm, are amorphous, morphologically homogeneous, and with essentially no contrast in the transmission electron microscopy (TEM) pictures. As the oxide thickness is increased up to 40 nm, a texture corresponding to the grain structure of the oxidized metal becomes gradually more visible. At the same time the oxide becomes increasingly more crystalline. The results are compared with previously published corresponding results for thicker anodic oxides on Ti.
TL;DR: In this paper, chemical vapor deposited diamond films were studied by scanning tunneling microscopy, and growth rates of 1.5 μm/h were obtained, on smaller scales amorphous structures with typical sizes less than 100 nm and individual equally sized clusters of approximately 5 nm in diameter.
Abstract: We have studied chemical vapor deposited diamond films by scanning tunneling microscopy. The films have been prepared in a hot‐filament reactor. The gas, a mixture of 1% methane and 99% hydrogen, is fed into the reactor by a pulsed high pressure valve. Growth rates of 1.5 μm/h were obtained. The films are defined by scanning electron microscopy (SEM), Raman spectroscopy, and x‐ray diffraction. On a scale similar to those normally found in SEM micrographs a 110 texture is shown. On smaller scales amorphous structures with typical sizes less than 100 nm and individual equally sized clusters of approximately 5 nm in diameter are observed.
TL;DR: In this article, the formation of MgO and yttria-stabilized ZrO2(YSZ) thin films on Si(100) substrates using laser (wavelength 248 nm pulse duration 40 ns, and repetition rate 5 Hz) physical vapor deposition method was investigated.
Abstract: We have investigated the formation of MgO and yttria‐stabilized ZrO2(YSZ) thin films on Si(100) substrates using laser (wavelength 248 nm pulse duration 40 ns, and repetition rate 5 Hz) physical vapor deposition method. The films were deposited from solid targets of MgO and polycrystalline YSZ in appropriate ambient with the substrate temperature optimized at 650 °C. The absorption coefficient in the MgO target was enhanced by Ni doping. The films were characterized using scanning and transmission electron microscopy (plan and cross section), x‐ray diffraction, and Rutherford‐backscattering spectrometry. The films were found to be polycrystalline with a texture. The thin films of MgO exhibited 〈111〉 texture, while the YSZ films contained both 〈111〉 and 〈200〉 textures.
TL;DR: In this article, high-quality c-axis oriented superconducting YBa2Cu3O7−δ thin films with CoSi2 buffer layers were obtained by in situ pulsed laser ablation processing.
Abstract: We have prepared high‐quality c‐axis oriented superconducting YBa2Cu3O7−δ thin films on Si (100) substrates with CoSi2 buffer layers by in situ pulsed laser ablation processing. The films were characterized by x‐ray diffraction, four‐point ac electrical resistivity, scanning electron microscopy (SEM), and transmission electron microscopy (TEM) techniques. YBa2Cu3O7−δ films were found to be textured with c axis perpendicular to the substrate. A plot of normalized resistance against temperature exhibited a metallic behavior followed by an onset superconducting transition at 91 K with zero resistance temperature (Tc0) of 83 K. Cross‐sectioned TEM results showed quite smooth interface between CoSi2 and Si with little interdiffusion; however, a reacted zone was observed between CoSi2 and YBa2Cu3O7−δ layers.