The colloidal silver solution was synthesized by reducing silver nitrate (AgNO 3 ) using sodium borohydride (NaBH 4 ) and starch as a stabilizer agent. The size and optical properties of synthesized AgNPs were characterized by UV-Vis spectroscopy, Fourier transforminfrared spectroscopy (FTIR) and transmission electron microscopy (TEM). The effects of several parameters on AgNPs were also investigated. The results have shown that the size of synthesized spherical silver nanoparticles was 8 ± 4 nm and disperse in water. The synthesized AgNPs of his study exhibited a strong antibacterial activity against Gram-negative bacteria Escherichia coli (E. coli) and Gram-positive Staphylococcus aureus (S. aureus). The average zones of inhibition of AgNPs were of 7.7 mm for bacteria E. coli and 7.0 mm for S. aureus. In this study, the zone of inhibition of AgNPs was also compared to the reference antibiotics drug.

We report on the electrical and optical characterisation of the high‐permittivity (high‐κ) TiO2 thin films grown by plasma enhanced atomic layer deposition on Si (100) and glass substrates, respectively. TiO2 films were incorporated in metal‐oxide semiconductor (MOS) capacitor structures with an Al metal gate electrode. The as‐deposited films were amorphous; however upon annealing in the temperature range 500–900 °C, crystalline TiO2 in the anatase phase was formed. This was further confirmed by performing Raman measurements where the characteristic features corresponding to the anatase phase were observed. Transmittance and absorption spectra of the as‐deposited and annealed films were performed by UV–Vis measurements showing more than 70% of transmittance. The formation of stoichiometric TiO2 was revealed by X‐ray photoelectron spectroscopy (XPS) and Rutherford backscattering spectroscopy (RBS) analysis performed on annealed samples (500–900 °C). The dielectric constants were calculated from capacitance–voltage (C–V) curves of the MOS structure on the as‐deposited film and annealed films revealing a significant improvement of the dielectric constants from 10 to 75 at AC frequencies of 100 kHz for the 700 °C annealed TiO2 thin films. The increase in the dielectric constant for annealed films could be attributed to the transformation of film structure from amorphous to polycrystalline (anatase). However, the transformation of amorphous to crystalline phase, leads to an increase in the leakage current which was also found best fitted with Schottky emission mechanism at moderated electric fields.

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A controlled pinning change from the ab-plane dominant to the c-axis dominant has been achieved in a novel method of nanostructured YBa 2 Cu 3 O x (YBCO) growth. The method is a synchronous self-assembly of BaZrO 3 (BZO) and Ag-assisted YBCO nanothreads. The formation of entangled nanothreads increases the critical current density while keeping the critical temperature close to that in pure YBCO films. The nanothreads extend through the whole thickness of thick films, making the method suitable for increasing total critical current density per centimeter of width (I c−w ). Two growth mechanisms, the formation of BZO nanorods and YBCO nanocolumns, complement each other, form a coherent structure and produce samples with strong correlated pinning. In addition to the increase in I c−w , correlated pinning leads to an increase in vortex melting temperature in a wide range of magnetic fields. The films grown by this method have high I c−w both in low magnetic fields along the c axis and high magnetic fields in the ab plane of YBCO. Such a superconductor would be suitable for both cable and magnet applications.

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