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MgB2 superconductor thin films, prepared by pulsed laser deposition (PLD) and electron beam evaporation (EBE), have been investigated by scanning electron microscopy (SEM) before and after 200 MeV 107Ag ion irradiation. The severe degradation of superconducting properties in irradiated PLD film and the absence of the same in EBE film correlates with the observed changes in their microstructures. The micrographs of the PLD film show an overall smoothing, flow pattern and reduction in size of the bigger agglomerates after irradiation. On the other hand, the microstructure of the EBE film does not show any significant change after irradiation. The flow pattern observed in the PLD film can be understood on the basis of the viscoelastic model for irradiation induced shear flow in amorphous solids. The observed degradation of the PLD film may thus be attributed primarily to its disordered nature under irradiation, whereas the radiation hardness of the EBE film may be due to its higher crystallinity.

We have presented here the results of SEM and STM/STS investigations carried out on MgB2 superconductor. The SEM pictures show porous surface and well-linked granular structure in which bigger grains (few micrometer size) seem to be agglomeration of smaller, nearly hexagonal grains (size nearly 100 nm). Hexagonal structure of Mg and B layers have been directly observed in atomically resolved STM images. The lattice constants have been determined to be aMg ¼ 3:1 AA, aB ¼ 1:7 AA and c ¼ 3:5 AA. Grain boundaries (GB) of width ranging from 50 to 200 AA have been observed. Absence of weak link effects despite wide GBs has been attributed to the metallic nature of the amorphous region of the GB interior as inferred from STS analysis. Irradiation with 200 MeV 107Ag ions gives tracks of about 65 AA in the bulk of the sample. This is expected to give higher value of critical current density owing to the flux pinning mechanism, which is related to possibility of wide practical application of this material.

Electrochromic hybrid thin films of cobalt hexacyanoferrate-polyaniline (CoHCF-PAni) have been synthesized by forming a film of K 2Co 2+[Fe 2+(CN) 6] followed by electropolymerization of PAni from an aqueous micellar solution. The hybrid film structure comprises cube like shapes with a face centered cubic lattice of CoHCF and fibers of PAni. Electrochemistry of hybrid films followed for the first time in an ionic liquid-1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide, revealed significant differences in their electrochromic and redox parameters in comparison with those observed for neat CoHCF and PAni films. Charge transfer, capacitive and diffusive phenomena were found to be controlled by the film microstructure, applied potential and the ingress-egress ability of the pyrrolidinium cation. The high coloring efficiency of 262 cm 2 C -1 at 687 nm under +0.4 V shown by the hybrid film and its ability to sustain 1000 cycles without much loss in optical contrast renders it suitable for use in electrochromic smart windows. © 2010 Elsevier B.V. All rights reserved.

Sodium phosphate glass systems with AgCl as dopant (0 and 15 mol%) have been synthesized by melt-quenching technique. The glasses in bulk form were characterized by X-ray diffraction, FT-IR spectroscopy and their thermal and electrical properties were investigated. These glasses were deposited on glass substrates by thermal evaporation method in thin film form and annealed at 600 °C. The influence of deposition in thin film form and annealing on structure and optical properties (transmittance, absorbance and optical gap) have showed that both doped and undoped as-deposited glass films have a porous, granular structure and considerable grain coarsening and densification occur upon annealing at 600 °C. The optical transmittance of the film is found to decrease in visible region as a function of annealing and doping. The annealed 15 mol% doped film shows a prominent absorbance peak at 430 nm, which is ascribed to Ag+(5s) ← O(n) electronic transitions. © 2010 Elsevier B.V. All rights reserved.

MgB2 superconductor thin films, prepared by pulsed laser deposition (PLD) and electron beam evaporation (EBE), have been investigated by scanning electron microscopy (SEM) before and after 200 MeV 107Ag ion irradiation. The severe degradation of superconducting properties in irradiated PLD film and the absence of the same in EBE film correlates with the observed changes in their microstructures. The micrographs of the PLD film show an overall smoothing, flow pattern and reduction in size of the bigger agglomerates after irradiation. On the other hand, the microstructure of the EBE film does not show any significant change after irradiation. The flow pattern observed in the PLD film can be understood on the basis of the viscoelastic model for irradiation induced shear flow in amorphous solids. The observed degradation of the PLD film may thus be attributed primarily to its disordered nature under irradiation, whereas the radiation hardness of the EBE film may be due to its higher crystallinity.

We have presented here the results of SEM and STM/STS investigations carried out on MgB2 superconductor. The SEM pictures show porous surface and well-linked granular structure in which bigger grains (few micrometer size) seem to be agglomeration of smaller, nearly hexagonal grains (size nearly 100 nm). Hexagonal structure of Mg and B layers have been directly observed in atomically resolved STM images. The lattice constants have been determined to be aMg ¼ 3:1 AA, aB ¼ 1:7 AA and c ¼ 3:5 AA. Grain boundaries (GB) of width ranging from 50 to 200 AA have been observed. Absence of weak link effects despite wide GBs has been attributed to the metallic nature of the amorphous region of the GB interior as inferred from STS analysis. Irradiation with 200 MeV 107Ag ions gives tracks of about 65 AA in the bulk of the sample. This is expected to give higher value of critical current density owing to the flux pinning mechanism, which is related to possibility of wide practical application of this material.