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Hydroxyapatite, a calcium phosphate compound, is a popular biomaterial due to its biocompatibility, bioactivity, biodegradability and non-toxicity. As strong candidates for interdisciplinary materials science applications, core-shell and hollow-core hydroxyapatite particles have emerged as promising materials with their capability for loading and releasing materials. This literature review provides a comprehensive overview of the synthesis and applications of micro- and nanostructured core-shell and hollow-core hydroxyapatite particles. Their applications in material loading, transfer and controlled release are highlighted and the potential of these particles for use in all disciplines of material transportation is emphasized. [ABSTRACT FROM AUTHOR]

In view of developing flexible, highly textured Pb-free piezoelectric thin films, (K,Na)NbO 3 was deposited by chemical solution deposition on cube-textured Ni-W alloy substrates. After heat treatment, a strong (001) pc out-of-plane preferential orientation is created in the (K,Na)NbO 3 layer, which also exhibits a sharp in-plane texture with 45°-rotated epitaxial relation to the substrate. The microstructure of the film is strongly dependent on the heat treatment temperature; sub-micrometer grains versus up to 2 μm long particles forming at 600 °C and 900 °C respectively. K 4 Nb 6 O 17 and (K 1−x Na x ) 2 Nb 4 O 11 impurity phases were identified depending on the processing temperature. [ABSTRACT FROM AUTHOR]

Abstract: We have numerically proved that the dependence of AC susceptibility χ of a E(J) power law superconducting thin disc on many parameters can be reduced to one penetration parameter h, with E the electric field and J the current density. Based on this result, we propose a way of measuring the critical current density J c of superconducting thin films by AC susceptibility. Compared with the normally used method based on the peak of the imaginary part, our method uses a much larger range of the AC susceptibility curve, thus allowing determination of the temperature (T) dependence of J c from a normally applied χ(T) measurement. A fitting equation J c =1.9H a ∣χ′∣0.69/d, −0.4< χ′<−0.001 derived from the critical state case (Bean model) can be used in most situations, where H a is the amplitude of the applied AC field, χ′ is the real part of the normalized susceptibility and d is the thickness of the film. The method is valid for the cases where the film is fully penetrated. We also discuss how the finite London penetration depth affects the susceptibility when the film is screened. Measurements with varying T, H a and DC background field H dc are performed to support the arguments. [Copyright &y& Elsevier]

ZnO films prepared on glass plates using a water based coating solution are characterized and tested for methylene blue dye photocatalytic decolourization in various types of waters (demineralized water, sea‐, and lake‐water). The influence of various parameters such as wavelength and attenuation of incident radiation by dye and/or organic matter is studied. In demineralized water, up to 90% decoloration is achieved within 1 h with 365 nm irradiation on a 10 ml solution. Although the ZnO films still show some activity when illuminated by standard visible light lamps, the efficiency of the photocatalytic process is greatly reduced. Natural waters result in a significant decrease of the photocatalytic activity, under both UV and visible light irradiation. The main factor is believed to be enhanced UV light absorption within the liquid. The influence of organic and mineral matter in natural waters is briefly discussed. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Alcohol dehydrogenase immobilized on four different inorganic powders. • Comparison between immobilization by physical adsorption and covalent bonding. • Buffer selection critical for enzyme and colloid suspension stability. • Activity retention of physically adsorbed enzyme controlled by electrostatic forces. Abstract Alcohol dehydrogenase from Saccharomyces cerevisiae was immobilized on different inorganic support materials, i.e. powders of Al 2 O 3 , SiC, TiO 2 and YSZ-8, by covalent bonding and physical adsorption. The raw powders were characterized by scanning electron microscopy, BET surface area, particle size distribution and ζ-potential measurements. Enzyme activity retention, storage stability and recyclability were evaluated on the basis of the measured support material properties. Preliminary experiments showed that the buffer selection was a critical factor. The properties of both the enzyme and the powders varied considerably between the buffers used; namely Tris-HCl (100 mM, pH 7) and MES (40 mM, pH 6.5) buffers. The enzyme activity was higher and more stable in the MES buffer, whereas the commonly used Tris buffer was problematic due to apparent incompatibility with formaldehyde. In MES, the order of decreasing activity of covalently bonded enzyme was on SiC > YSZ-8 > Al 2 O 3 > TiO 2. The lower performance of TiO 2 was ascribed to the negative ζ-potential of the material, which impeded an efficient immobilization. Particle agglomeration, caused by low colloidal stability of the particles in MES buffer, hampered the storage stability of the immobilized systems. The results from this study show the advantages and limitations of using nanoparticles as immobilization supports, and highlight which properties of nanoparticles must be considered to ensure an efficient immobilization. [ABSTRACT FROM AUTHOR]

Abstract: A fluorine-free aqueous sol–gel technique was used to fabricate YBCO superconducting thin films. Acetic acid was added in order to modify the complexation process taking place between the metal cations and the organic chelating agents. The electrical resistance and the pH value were used as indicators of the quality of the precursors. When pH=6.5, the precursor solution had the lowest resistance, implying a good ionization of the starting metal elements. By using the optimal precursor, the film was found to have very small sized particles after pyrolysis. Consequently, the annealed YBCO films are characterized by a sharp superconducting transition with a Jc (77K) of 0.25MA/cm2. [Copyright &y& Elsevier]

In spite of many years of research, the physical phenomena leading to the evolution of compacted graphite (CG) during solidification is still not fully understood. In particular, it is unknown how highly branched CG aggregates form and evolve in the semi-solid, and how local microstructural variations at micrometer length scale affect this growth process. We present here the first time-resolved synchrotron tomography combined with a bespoke high-temperature environmental cell that allows direct observation of the evolution of CG and relates this dynamic process to the local surrounding microstructures in a cast iron sample during repeated melting and solidification. Distinct processes are identified for the formation of CG involving the nucleation, growth, development of branches and interconnection of graphite particles, ultimately evolving into highly branched graphite aggregates with large sizes and low sphericities. CG is found to nucleate with a spheroidal or a plate-like shape, developing branches induced by high carbon concentration, e.g. thin melt channels. Additionally, CG grows much faster than spheroidal graphite during subsequent cooling in solid state. The direct visualization of the dynamic solidification process provides unprecedented new insights into formation mechanisms of CG and correlating factors such as local microstructural variations, and guides the development of CG iron solidification models. [Display omitted] [ABSTRACT FROM AUTHOR]

We report a novel doping strategy for YBa 2 Cu 3 O 7-x (YBCO) superconducting films by using a positive mismatch, Ba 2 YNbO 6 (BYNO), and a negative mismatch, LaAlO 3 (LAO), simultaneously. Double doping can significantly reduce the c -strain in the YBCO film by canceling the strain between the two dopants. By systematically optimizing the doping amount of both BYNO and LAO, it was found that BYNO and LAO do not act equally. The microstructure and distribution of both BYNO and LAO were investigated with magneto-optic microscopy and scanning electron microscopy. The effect of BYNO and LAO on pinning was confirmed. The results of this study will help select appropriate positive mismatch and negative mismatch dopants, which is fundamental to the design and fabrication of pinning centers to fit different application scenarios. [ABSTRACT FROM AUTHOR]

Abstract: Enzyme immobilization is an established method for the enhancement of enzyme stability and reusability, two factors that are of great importance for industrial biocatalytic applications. Immobilization can be achieved by different methods and on a variety of carrier materials, both organic and inorganic. Inorganic materials provide the advantage of high stability and long service life which, together with the prolonged service life of the immobilized enzyme, can benefit the process economy. However, enzyme immobilization and increased stability often come at the cost of decreased enzyme activity. The main challenges involved in the design of an efficient immobilized enzyme system is to obtain both retention of high enzyme activity, enhanced stability and reusability, which is a complicated task, given the many variables involved, and the large numbers of methods and materials available. Simultaneously, new carrier materials and morphologies are constantly being developed. An investigation of enzyme immobilization systems on inorganic materials, with special emphasis on inorganic membranes, has been conducted in order to evaluate the effects of the immobilization system on the enzyme properties upon immobilization, i.e., activity, stability and reusability. The material properties of the enzyme carriers (particles and membranes) and their effects on the success of immobilization are described here. Furthermore, the reuse of inorganic membranes as enzyme carriers has been investigated and the reported examples show high ability of regeneration. To the best of our knowledge, this is the first review on enzyme immobilization focusing on the three fundamental aspects to consider when dealing with the topic: catalytic properties, enzyme leakage and reusability. Abbreviations: β‐Gal: β‐ d‐galactosidase; ADH: alcohol dehydrogenase; AFM: atomic force microscopy; APTES: 3‐aminopropyltriethoxysilane; APTMS: 3‐aminopropyltrimethoxysilane; BPA: bisphenol A; BSA: bovine serum albumin; CA: carbonic anhydrase; CALB: Candida antartica lipase B; CD: circular dichroism; CDI: carbonyldiimidazole; CLEA: cross‐linked enzyme aggregates; CLSM: confocal laser scanning microscopy; CNT: carbon nanotube; CPG: controlled pore glass; CRL: Candida rugosa lipase; DMeDMOS: dimethyldimethoxysilane; DRIFT: diffuse reflectance Fourier transform infrared; E2: 17β‐estradiol; EDC: N‐(3‐dimethylaminopropyl)‐N′‐ethylcarbodiimide hydrochloride; EDS: electron dispersive spectroscopy; FDH: formate dehydrogenase; FESEM: field emission scanning microscopy; FT‐IR: Fourier transform infrared spectroscopy; GA: glutaraldehyde; GCSZn: coal fly ashes glass‐ceramic zinc sulfate; GOD: glucose oxidase; GPS: 3‐(glycidyloxypropyl)trimethoxysilane; HDMI: hexamethylene diisocyanate; HRP: horseradish peroxidase; IEP: isoelectric point; IPTES: (3‐isocyanatopropyl)triethoxysilane; IR: infrared spectroscopy; LbL: layer‐by‐layer: MCP: metallic ceramic powder; MeTEOS: methyltriethoxysilane; MF: microfiltration; MML: Mucor miehei lipase; MNP: magnetic nanoparticle; MPTMS: 3‐mercaptopropyltrimethoxysilane; NHS: N‐hydroxysuccinimidyl; PAH: poly(allylamine hydrochloride); PEI: polyethyleneimine; PEG: polyethylene glycol; PES: polyether sulfone; PM‐IRRAS: polarization modulation infrared reflection absorption spectroscopy; pNPA: para‐nitrophenyl acetate; pNPP: para‐nitrophenyl palmitate; PSS: polystyrene sulfonate; PTMS: phenyltrimethoxysilane; ROL: Rhizopus oryzae lipase; SCAD: Saccharomyces cerevisiae alcohol dehydrogenase; SDS: sodium dodecyl sulfate; SDS‐2: sodium dodecyl sulfonate; SEM: scanning electron microscopy; TEM: transmission electron microscopy; TEOS: tetraethoxysilane; TGA: thermogravimetric analysis; TLL: Thermomyces lanuginosa lipase; TMP: transmembrane pressure; TTIP: titanium tetraisoproxide; TVL: Trametes versicolor laccase; UF: ultrafiltration; VTMS: vinyltrimethylsilane [ABSTRACT FROM AUTHOR]

The two level undercut-profile substrate (2LUPS) has been introduced as a concept for subdividing rare-earth-Ba2Cu3O7 coated conductors (CC) into narrow filaments that effectively reduces the ac losses and improves field stability for dc magnets. The 2LUPS consists of two levels of plateaus connected by a wall with an undercut-profile, which enables a physical separation of the superconducting layer between the plateaus without reducing the effective width of the superconducting layer. In this study, we report for the first time the results of fabrication and characterization of a filamentary CC produced in an industrial setup by SuperPower Inc. using ion beam assisted deposition and metal organic chemical vapor deposition (IBAD-MOCVD) on a 2LUPS realized at the Technical University of Denmark, whereas previous studies discussed the fabrication using alternating beam assisted deposition and pulsed laser deposition (ABAD-PLD). We also present Hall probe scanning measurements performed using a standard THEVA TAPESTAR XL machine that is routinely employed for industrial critical current characterization of long length CCs. From these results is it clear that additional analysis of the measured field profiles are required when characterizing filamentary 2LUPS CC using a standard TAPESTAR setting. Using a model representation of the 2LUPS we calculated the expected magnetization response by means of finite element methods simulations and we find a good agreement with the experimentally observed magnetic profiles. [ABSTRACT FROM AUTHOR]

Microstructure and superconducting performance of YBa 2 Cu 3 O 7 (YBCO) films deposited on LaAlO 3 single crystal (LAO) substrates by a fluorine-free metal-organic deposition (FF-MOD) technique, have been studied by means of X-ray reciprocal space mapping (RSM), cross-sectional transmission electron microscopy (TEM) and magneto-optical (MO) imaging. Combining the X-ray diffraction and the TEM cross-sectional analysis, it is revealed that stacking faults, i.e. YBa 2 Cu 4 O x intergrowths, and ab -plane twins are main defects in the FF-MOD YBCO films. Due to the highly epitaxial growth mechanism related to transient liquid phase, the LAO twinned substrate structure is also inherited in the FF-YBCO films. The low-density planar defects containing dislocations parallel to c -axis result in stripy patterns observed in the MO images. For comparison, the low-fluorine (LF) MOD film show a texture mosaic spread in the ab plane and is little influenced by the LAO twinning underneath, implying the severe structural disorder most likely associated with the large amount of small-angle grain boundaries. Moreover, the higher density of stacking faults was also detected by XRD θ−2θ scan in the LF-MOD film. It is suggested that associated partial dislocations formed at the boundary between the stacking faults and YBCO matrix act as strong linear (or dot) pinning centers. These structural characteristics are well in line with the better superconducting performance of the low fluorine-MOD film, in particular under external magnetic field at 77 K. This work offers an in-depth insight into the correlation between the microstructure and superconductivity in the MOD YBCO films. [ABSTRACT FROM AUTHOR]

Pulsed laser deposition is often considered a process providing congruent transfer of target composition to the growing film. In fact, many different processes affect compositional preservation, starting from incongruent target ablation, to scattering on the way to the substrate, and to processes of the film formation on the substrate surface. We developed a pulsed laser deposition process trying to minimize the compositional deviations due to the scattering by the ambient gas by applying laser beam scanning across the target surface and substitution of oxygen with argon in the chamber during deposition. Transfer of elemental composition of YBaCuO targets with compositions varying from stoichiometric 1/2/3 ratio was tested by deposition of thin films in conditions optimal for high-temperature superconductor formation. Despite all measures, the films still show Ba,Y enrichment due to different efficiencies of scattering on the ambient gas. The Y part in the film followed well the composition of the target, but the Ba enrichment was almost constant for most of the studied target compositions, implying a crucial role of the film growth processes. The YBaCuO (YBCO) films show a layered structure, with increased density of defects in the topmost layer. We suppose this is due to expelling of the excess Ba into the top layer with formation of a quasi-liquid layer promoting formation of a high-density YBCO film. [ABSTRACT FROM AUTHOR]

We report on the results of a YBaCu O (YBCO) superconductive transition edge bolometer (TEB) fabricated on a CeLa O (CLO) buffered single crystalline yttria-stabilized zirconia (YSZ) substrate. Metal organic deposition was used for the fabrication of both the YBCO thin film as well as CLO buffer layer, while standard photolithography was applied for TEB preparation. YBCO thin film properties were analysed using scanning electron microscopy (SEM), X-ray diffraction (XRD), AC susceptibility and resistance versus temperature measurements. Optical response of the TEB in terms of voltage amplitude and phase was analysed and measured through four-probe technique in a liquid nitrogen cooling system. An increase in voltage amplitude response was observed for the fabricated YBCO/CLO/YSZ bolometer compared to previously reported TEBs with similarly deposited YBCO thin film on a SrTiO (STO). This increase is assumed to be a result of the lower thermal conductivity and lower specific heat capacity of YSZ compared to STO substrate. [ABSTRACT FROM AUTHOR]

Intensive investigations have been conducted to develop epitaxial oxide thin films with superior electromagnetic performance by low-cost chemical solution deposition routes. In this paper, a novel propionate-based precursor solution without involving any other additive was proposed and employed to grow superconducting YBa2Cu3O7−δ (YBCO) films on LaAlO3 (LAO) single crystals. The precursor solutions are stable with a long shelf life of up to several months. Since the primary compositions are propionates after evaporating the solvent, the toxic reagents and evolved gases during solution synthesis and heat treatment can be eliminated completely. In this process, rapid pyrolysis and high conversation rate can also be achieved during growth of YBCO films in comparison with the conventional trifluoroacetate metal organic deposition routes. Remarkably, a 210 nm YBCO film exhibits high superconducting performance with a Jc value of 3.7 MA/cm² at 77 K, self-field. Nucleation and growth behaviors in the chemical solution process have also been studied. It is revealed that the amount of liquid phase (Ba–Cu–O) is sufficient through the entire thickness within a very short time at high growth temperatures, which results in pronounced densification and fast conversion of the YBCO phase. [ABSTRACT FROM AUTHOR]

A 10-m-long homemade textured Ni-5at.%W (Ni5W) long tape with a CeO buffer layer has been prepared successfully by means of rolling-assisted biaxially textured substrate (RABiTS) route followed by a chemical solution deposition method in a reel-to-reel manner. Globally, the Ni5W substrate and CeO film exhibit high homogeneity in terms of biaxial texture over the tape. The average values of full width at half maximum of in-plane and out-of-plane texture are 7.2° and 6.1° in Ni5W substrate, 7.6° and 6.1° in CeO buffer layer, respectively, all of those with a small standard deviation. On a microlevel, the CeO film epitaxially grows well on top of the Ni5W tape. A continuous, smooth, and crack-free morphology was observed on the CeO film and the fraction of low-angle grain boundaries (≤ 10°) is about 98 %. This process is a potential possibility for producing long-length textured CeO/Ni5W tapes for coated conductors with a low cost. [ABSTRACT FROM AUTHOR]

Two types of Cu–45 at%Ni alloy thin tapes with and without surface shear were obtained by different heavy cold rolling processes. The deformation and recrystallization textures of the two tapes were thoroughly investigated by electron back scattering diffraction technique. The results showed that a shear texture mainly covered the surface of the heavy deformed tapes because of the fraction between the surface of rolling mills and the thin tapes when the rolling force strongly reduced at high strain, which significantly reduced the fraction of rolling texture on the surface of the Cu–45at %Ni alloy thin tapes, retarded the cube grain growth during recrystallization and affected the strong cube texture formation after high temperature annealing. [ABSTRACT FROM AUTHOR]

Synthetic copper(II) oxalate, CuC2O4, was obtained in a precipitation reaction between a copper(II) solution and an aqueous solution of oxalic acid. The product was identified from its conventional X-ray powder patterns which match that of the copper mineral Moolooite reported to have the composition CuC2O4·0.44H2O. Time resolved in situ investigations of the thermal decomposition of copper(II) oxalate using synchrotron X-ray powder diffraction showed that in air the compound converts to Cu2O at 215 °C and oxidizes to CuO at 345 °C. Thermo gravimetric analysis performed in an inert Ar-gas reveals that the material contains no crystal water and reduces to pure Cu at 295 °C. Magnetic susceptibility measurements in the temperature range from 2 K to 300 K show intriguing paramagnetic behaviour with no sign of magnetic order down to 2 K. A crystal structure investigation is made based on powder diffraction data using one neutron diffraction pattern obtained at 5 K (= 1.5949(1) Å) combined with one conventional and two synchrotron X-ray diffraction patterns obtained at ambient temperature using = 1.54056, 1.0981 and = 0.50483(1) Å, respectively. Based on the X-ray synchrotron data the resulting crystal structure is described in the monoclinic space group P21/c (#14) in the P121/n1 setting with unit cell parameters a = 5.9598(1) Å, b = 5.6089(1) Å, c = 5.1138 (1) Å, ß = 115.320(1)°. The composition is CuC2O4 with atomic coordinates determined by FullProf refinement of the neutron diffraction data. The crystal structure consists of a random stacking of CuC2O4 micro-crystallites where half the Cu-atoms are placed at (2a) and the other half at (2b) positions with the corresponding oxalate molecules centred around the corresponding (2b) and (2a) site positions, respectively. The diffraction patterns obtained for both kinds of radiation show considerable broadening of several Bragg peaks caused by highly anisotropic microstructural size and strain effects. In contrast to the water reported to be present in Moolooite, neither thermogravimetric nor the in situ thermal decomposition investigations and crystal structure analysis of the neutron diffraction data revealed any trace of water. An appendix contains details about the profile parameters for the diffractometers used at the European Synchrotron Radiation Facility and the Institute Max von Laue-Paul Langevin. [ABSTRACT FROM AUTHOR]

In view of high rate fabrication of coated conductors at low-cost, YBa2Cu3O7 (YBCO) films on Ce0.9a0.1O2-y buffered yttria-stabilized zirconia substrates were deposited by means of a novel low-fluorine metal-organic solution route. A high critical current density of 3 MA cm-2 (77 K, self field) was achieved on such an all-chemical derived configuration. Structural characterization showed that the enhanced superconductivity performance of the YBCO films is mainly related to the defects induced by the interface. [ABSTRACT FROM AUTHOR]

In previously reported low-fluorine MOD-YBCO studies, the lowest F/Ba mole ratio of the precursor solution was 4.5. Further lowering the F/Ba ratio would bring benefits for the environment, thick film deposition, and an understanding of the heat treatment process. On the other hand, the F/Ba ratio must be at least 2 for full conversion of the Ba-precursor to BaF2 to avoid the formation of BaCO3, which is detrimental to the superconducting performance of YBCO films. In this study, a solution with a 2:1 F/Ba mole ratio was developed, and the fluorine content of this solution was approximately only 10.3% of that used in the conventional TFA-MOD method. Attenuated total reflectance-Fourier transform-infrared spectra (ATR-FT-IR) revealed that BaCO3 was remarkably suppressed in the as-pyrolyzed film—and eliminated at 700 °C. Thus, YBCO films with a critical current density (Jc) of over 5 MA cm−2 (77 K, 0 T, 200 nm thickness) could be obtained on lanthanum aluminate single-crystal substrates. In situ FT-IR spectra showed that no obvious fluorinated gaseous by-products were detected in the pyrolysis step, which indicated that all F atoms might remain in the film as fluorides. X-ray diffraction θ/2θ scans showed the presence of BaF2—but not of Y F3 or CuF2—in films quenched at 400–800 °C. The formation priority of BaF2 over Y F3 and CuF2 was interpreted by examining the chemical equilibrium of the potential reactions. Our study could enlarge the synthesis window of precursor solutions for MOD-YBCO fabrication, and serve as a foundation for continuously and systematically studying the influence of fluorine content in the precursor solutions. [ABSTRACT FROM AUTHOR]

Trifluoroacetate metal–organic deposition (TFA-MOD) is a promising technique to fabricate YBa2Cu3O7-δ (YBCO) superconducting films. However, its slow pyrolysis process, which usually takes more than 10 h, constitutes a barrier for industrial production. In this study, polyethylene glycol (PEG) was utilized to reduce the stress generation inside the coated films when the strong pyrolysis reactions happen. With the addition of 30 wt% PEG2000 to the precursor solution, a smooth film surface could be obtained through a rapid pyrolysis process of 15 min. After the optimizations of the crystallization and oxygenation processes, mass percentage and molecular weight of PEG additive, YBCO thin films with Jc of about 4:5 MA cm-2 (77 K, self-field) could be routinely fabricated using (20-30) wt% PEG(1000-2000) additive with a total treatment time of about 2 h including the 15 min pyrolysis process time. The effects of PEG additive were discussed using one of the mechanisms of buckling formation. The reduction of compressive stress by PEG additive was suggested to be the reason for preventing buckling. [ABSTRACT FROM AUTHOR]

Abstract: The effects of excess yttria on the structural and electrical properties of the YBa2Cu3O x (YBCO) thin films are studied. The films were deposited on (LaAlO3)0.3–(Sr2AlTaO8)0.7 substrates by pulsed laser ablation from targets with different elemental composition. An increase of yttrium content of the target leads to formation of porous films with significantly improved current-carrying capabilities. Structural studies of these films reveal presence of yttria nanoparticles embedded into the YBCO matrix. The highest obtained critical current density in an external magnetic field of 5T was 2.6MA/cm2 at 50K and 9.4MA/cm2 at 20K. The fabricated Y-enriched YBCO films remain c-oriented at least up to 600nm thickness with no significant suppression of the critical current density. [Copyright &y& Elsevier]

The microstructural and compositional evolution during initial annealing of a superconducting (Bi,Pb)2Sr2Ca2Cu3O10+δ/Ag tape is studied using quantitative transmission electron microscopy. Special attention is devoted to the occurrence of Pb-rich liquids, which arc crucial for the Bi2Sr2CaCu2O8+&delta to (Bi,Pb)2Sr2Ca2Cu3O10+δ transformation, Ca and/or Pb-rich (Bi,Pb)2Sr2CaCu2O8+&delta grains dissolve into a liquid, which reacts with Ca-rich phases to increase the liquid's Ca-content. This leads to (Bi,Pb)2Sr2Ca2Cu3O10+δ formation. Apparently, a Ca/Sr ratio of around I is sufficient to keep (Bi,Pb)2Sr2Ca2Cu3O10+δ a nucleation going. It is confirmed that Ag particles are transported from the Ag-sheath into the oxide core by the liquid and not by mechanical treatment of the tape. [ABSTRACT FROM AUTHOR]

Superconducting YBa2Cu3O7-δ (YBCO) films are deposited on LaAlO3 single crystals from fluorine-free 1.5-1.7 M precursor solutions containing a stoichiometric mixture of Y, Ba, and Cu acetates in propionic acid (80 °C, 1 h). [ABSTRACT FROM AUTHOR]