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Ni nanoparticle-added Ni x /(Cu0.5Tl0.5)Ba2Ca2 Cu3 O 10-δ superconductor composites are synthesized at normal pressure by two-step solid-state reaction method. The idea for adding ferromagnetic nanoparticles was to create artificial pinning centers at grain boundaries. The samples have shown orthorhombic crystal structure in which the cell parameters increase with an increase in the added concentration of Ni nanoparticles. This shows that due to the higher reactivity, Ni nanoparticles partially diffuse into the unit cell of (Cu0.5Tl0.5)Ba2Ca2Cu3 O 10-δ superconductors. This also indicates as an evidence of the occupancy of these nanoparticles at grain boundaries. A metallic variation of resistivity from room temperature down to the onset of superconductivity is a typical feature of these samples with T c (R = 0) varying between 92 and 94 K. The magnitude of diamagnetism is significantly enhanced in 7 and 10% nanoparticle-added samples. The enhanced magnetization of ferromagnetic nanoparticles at reduced temperature plays a vital role in reducing the diamagnetism of nanosuperconductor composites. The softening of apical oxygen modes of type Cu(1)–OA–Cu(2) has confirmed the diffusion of Ni nanoparticles into the unit cell of the final compound. The excess conductivity analyses of conductivity data have shown that the values of B c (0), B c1, and J c are enhanced with the addition of Ni nanoparticles in the final compound. Variation of superconducting properties was attributed to pair breaking due to spin scattering across these ferromagnetic Ni nanoparticles. This shows that added Ni nanoparticles act as efficient pinning centers, which is also confirmed by the suppression of the London penetration depth.

(CoFe2O4)x/Cu0.5Tl0.5Ba2Ca2Cu3O10−δ {(CoFe2O4)x/CuTl-1223}; (0 ≤ x ≤ 2) nanoparticles-superconductor composites were synthesized by solid–state reaction technique and dissipative mechanism was investigated by infield measurements and analysis. Activation energy {Uo(H)} was calculated from Arrhenius plots of infield resistivity measurements. The infield resistive properties of superconductors depend upon the fluxoid motion, which causes resistive transition broadening by shifting Tc (0) towards lower temperature values. The enhancement of transition broadening is attributed to spread of upper critical field in vortex state and dissipation process with applied magnetic field. Addition of magnetic CoFe2O4 nanoparticles reduces the fluxoid motion by introducing nano-sized defects in the host CuTl-1223 superconducting matrix, which act as effective flux pinning centers. An overall increase in the activation energy Uo(H) has been observed with increasing contents of magnetic CoFe2O4 nanoparticles, which elucidate the enhanced flux pinning with increasing CoFe2O4 magnetic nanoparticles content up to x = 1.5 wt. % in CuTl-1223 superconducting matrix.

We have synthesized Ti-doped (Tl $$_{1-x}$$ Ti $$_{x})$$ Ba $$_{2}$$ Ca $$_{2}$$ Cu $$_{3}$$ O $$_{y}$$ (x = 0, 0.2, 0.4, 0.6, 0.8) superconductors at normal pressure. The samples have shown $$T_\mathrm{c}$$ onset at 117, 118, 113, 110, and 115 K and the $$T_\mathrm{c}$$ $$(R=0)$$ at 103, 96, 94, 97, and 106 K and the onset of diamagnetism around 109, 100, 98, 111, 100 K, respectively. The apical oxygen-related phonon modes are observed around 485 and 540 cm $$^{-1 }$$ , and the planar oxygen modes at 600 cm $$^{-1}$$ . These phonon modes are softened with the increase concentration of Ti in the final compound showing that Ti is incorporated into the (Tl $$_{1-x}$$ Ti $$_{x})$$ Ba $$_{2}$$ Ca $$_{2}$$ Cu $$_{3}$$ O $$_{y}$$ (x = 0, 0.2, 0.4, 0.6, 0.8) samples. The excess conductivity analysis of these samples has shown an enhancement in the values of the parameters such as $$\xi _{\mathrm{c}(0)}$$ , J, and $$V_\mathrm{F}$$ with the doping of Ti. We proposed that the doping of Ti in the $$( {\mathrm{Tl}_{1-{\textit{x}}} \mathrm {Ti}_{{x}} })\mathrm{Ba}_2 \mathrm{O}_{4-\delta } $$ charge reservoir layer facilitates the charge transfer mechanism for conducting CuO $$_{2}$$ planes which in turn enhance the values of aforementioned superconductivity parameters. The values of superconductivity parameters such as $$B_\mathrm{c(0), }$$ $$B_\mathrm{c1(0), }$$ $$B_\mathrm{c2(0)}$$ , and $$J_\mathrm{c}$$ (0) are, however, suppressed with Ti doping. We suggested this to be arising from the weakening of flux pinning character in the final compound. These results have shown that the oxygen defect density in (Tl $$_{1-x}$$ Ti $$_{x})$$ Ba $$_{2}$$ Ca $$_{2}$$ Cu $$_{3}$$ O $$_{y}$$ samples is significantly suppressed with Ti doping.

We have used two-step solid state reaction method for the synthesis of (Cu0.5Tl0.5)Ba2Ca3(Cu4−y Ti y ) O12−δ (y = 0, 0.25, 0.50, 0.75, 1.0) superconductors at 880 °C. The oxygen contents in the samples were optimized by carrying out self-doping which is accomplished by post-annealed in flowing oxygen environment at 500 °C for approximately 5 h. The superconducting properties of all the samples were improved, after the self-doping of the carriers in the conducting planes. In the x-ray diffraction scans of the samples, the a-axis length of tetragonal unit cell increases whereas the c-axis decreases with increased Ti doping in the final compound. The Fourier transform infrared spectrometer (FTIR) absorption measurements of these samples have shown that the apical oxygen mode at 548 cm−1 and the planar oxygen mode at 596 cm−1 are softened with increased Ti doping. The origin of softening of planar oxygen mode lies in increase bond lengths of apical oxygen atoms promoted by larger covalent radius of Ti (1.32 A) atoms relative to Cu (1.17 A) atoms that in turn promotes the softening of the apical oxygen modes. Doped Ti (47.90 amu) atoms at the Cu (63.54 amu) sites initiate the an-harmonic oscillations resulting into the suppression of density of phonon modes. The suppression in the values of superconductivity parameters with Ti doping at the Cu sites shows the essential role of phonon in mechanism of high Tc superconductivity and hence the electron–phonons interactions. The excess conductivity analyses (FIC) of conductivity data of oxygen-post-annealed samples have shown decrease in the mean field critical temperature, coherence length along the c-axis, interlayer coupling, and Fermi velocity with increase Ti doping. However, the values of B c, B c1, and J c(0) increase with Ti doping, showing increase in the population of the pinning centers.

Highly oriented crystalline aluminum doped zinc oxide (AZO) films were sputter deposited on glass substrates and a systematic investigation on the as deposited and etched films was reported for its further application in silicon thin film solar cell. Influence of the deposition pressure (from 2 to 8 mTorr) and post-annealing temperature (at 400 °C for 5 min) on the structural, optical and electrical properties of the as-deposited and etched samples were analyzed. The optimum condition for its reproducibility and large area deposition is determined and found that the depositions made at 8 mTorr at 200 W having the distance from source to substrate of 9 cm. All the AZO films exhibited a c -axis preferred orientation perpendicular to the substrate and their crystallinity was improved after annealing. From the XRD pattern the grain size, stress and strain of the films were evaluated and there is no drastic variation. Optical transmittance, resistivity, Hall mobility and carrier concentration for the as deposited and etched-annealed films were found to improve from 79 to 82%; 2.97 to 3.14×10 −4 Ω cm; 25 to 38 cm 2 /V s; 8.39 to 5.96×10 20 /cm 3 respectively. Based on the triangle diagram between figure of merit and Hall mobility, we obtained a balance of point between the electrical and optical properties to select the deposition condition of film for device application.

Cu0.5Tl0.5Ba2Ca3Cu4O12−δ /(Fe–Pd 0, 0.5, 1.0, 1.5 %) superconductors are prepared at normal pressure by using three-step method. Alloy of Cu0.5Tl0.5Ba2Ca3 Cu4O12−δ /(Fe–Pd 1 %) have shown maximum increase in the magnitude of superconductivity. Cu 0.5Tl 0.5 Ba2Ca 3Cu 4 O 12−δ /(Fe–Pd 0, 0.5, 1.0, 1.5 %) samples have shown T c(R= 0) around 106, 105.3, 102, and 100 K and the onset of diamagnetism around 113, 110, 102, and 105 K, respectively. A comparison of X-ray diffraction (XRD) scans of Fe–Pd nanoparticles with Cu0.5Tl0.5Ba2Ca3Cu4 O 12−δ /(Fe–Pd 0.5, 1.0, 1.5 %) superconducting samples have shown that the nanoparticles of Fe–Pd are quite stable in the matrix of Cu0.5Tl0.5Ba2Ca3Cu4 O 12−δ samples even after repeated firing at 890 ∘C. With increase addition of Fe–Pd nanoparticles, the axes length increases, showing some inclusion of nanoparticle into the unit cell of Cu0.5Tl0.5Ba2Ca3Cu4 O 12−δ samples from the termination ends of crystal.The inclusion of Fe–Pd in the superconducting Cu0.5Tl0.5Ba2Ca3Cu4 O 12−δ grains is also evidenced in Fourier transform infrared spectroscopy (FTIR) absorption measurements. The Fe–Pd nanoparticles added in Cu0.5Tl0.5Ba2Ca3Cu4 O 12−δ samples have been found to decrease the population of inter-grain voids that is found to increase the coherence length along the c-axis and the inter-layer coupling J. The FIC analysis of conductivity data haveshown the Fe–Pd nanoparticles diffusing into the inter-grain sites promoted an increase of penetration depth λ p.d and Ginzburg–Landau parameter, κ. Due to the this possible diffusion of the Fe–Pd nanoparticles in the superconducting grains, the T c(R= 0), B c0(T), B c1(T), and J c(0) values are suppressed in Cu0.5Tl0.5Ba2Ca3Cu4 O 12−δ samples.

We have synthesized (Cu0.5Tl0.5)Ba2Ca3(Cu4−x Ti x )O12−δ (x = 0, 0.25, 0.50, 0.75, 1.0) superconductors by two-step solid-state reaction method at 880 °C. The a-axis length of tetragonal unit cell increases, whereas the c-axis decreases with doping of Ti in the final compound revealed by X-ray diffraction measurements. Moreover, the magnitude of superconductivity suppresses with increased Ti doping. The Fourier transform infrared spectrometer (FTIR) absorption measurements have shown that the peak position of the apical oxygen modes at 480 and 540 cm −1 remains unchanged, whereas the CuO2/TiO2 planar oxygen modes is softened with increased Ti doping. We explained the softening of planar oxygen mode to be arising due to the difference in the atomic masses of Ti (47.90 amu) and Cu (63.54 amu) atoms. The suppression of superconductivity magnitude is suggested to be originating from an-harmonic oscillations induced by doped Ti atoms which in turn suppress the density of phonon population. These studies show the importance of density of phonon population in mechanism of high- T c superconductivity and hence the electron-phonon interactions. The excess conductivity analyses (FIC) of conductivity data of these samples have shown that with increased Ti doping, the mean field critical temperature T cmf is shifted to lower temperatures. The increase in the coherence length along the c-axis, interlayer coupling, and the Fermi velocity is suggested to be arising from the decrease in the c-axes length. We attribute the suppression in B c, B c1, J c(0), and τ ϕ with Ti doping to the free energy difference between the normal and superconducting state. The idea of suppression in the density of phonon modes induced by Ti doping is supported by excess conductivity analyses.

To explore the flow characteristics of healing agent leaving a vascular network and infusing a damage site within a fibre reinforced polymer composite, a numerical model of healing agent flow from an orifice has been developed using smoothed particle hydrodynamics. As an initial validation the discharge coefficient for low Reynolds number flow from a cylindrical tank is calculated numerically, using two different viscosity formulations, and compared to existing experimental data. Results of this comparison are very favourable; the model is able to reproduce experimental results for the discharge coefficient in the high Reynolds number limit, together with the power-law behaviour for low Reynolds numbers. Results are also presented for a representative delamination geometry showing healing fluid behaviour and fraction filled inside the delamination for a variety of fluid viscosities. This work provides the foundations for the vascular self-healing community in calculating not only the flow rate through the network, but also, by simulating a representative damage site, the final location of the healing fluid within the damage site in order to assess the improvement in local and global mechanical properties and thus healing efficiency.