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Thermal oxidation of cube textured, pure Ni and Ni–Cr tapes was undertaken under different oxidation conditions to form cube textured NiO for the use as a first component of buffer layer for the coated conductor. Cube textured NiO was formed on pure Ni after oxidising for more than 130 min in O2 at 1250 °C. The oxide thickness was >30 μm. Much shorter oxidation times (20–40 min, NiO thickness of ∼5 μm) and lower temperature (1050 °C) were required to form a similar texture on Ni–Cr foils. In addition, NiO formed on Ni–13%Cr was more highly textured than Ni–10%Cr. A Cr2O3 inner layer and NiO outer layer was formed on the Ni–Cr alloys. [Copyright &y& Elsevier]

Abstract: Raman spectra of a series of thin films of the superconductor MgB2 have been measured as a function of the T c of the films. An interesting correlation is observed between the Raman shift of the E 2 g mode and the T c. We propose a mechanism for the T c reduction, which has consequences for the behaviour of the two superconducting gaps in MgB2 for samples of very reduced T c (≤19K). Additionally, the effects of oxygenation on the properties of MgB2 have been studied in order to develop an understanding of the effects of structural distortion in this material. [Copyright &y& Elsevier]

Abstract: The utilization of metal-organic decomposed cerium oxide (CeO2) film as a gate oxide spin-coated on n-type GaN and SiC for metal-oxide-semiconductor structure has been investigated. Post-deposition annealing (PDA) in oxygen ambient at 1000°C was performed on both CeO2/GaN and CeO2/SiC systems while a higher PDA was carried out on CeO2/SiC system at 1150°C. The cross-sectional images of scanning transmission electron microscopy (STEM) and elemental line profiles of energy dispersive X-ray verified the formation of interfacial layer (IL) and its compound. It had been perceived from STEM that decomposition of GaN substrate during PDA at 1000°C had led to the crack formation on the surface of GaN and this issue was not confronted by the SiC substrate. From X-ray diffraction analysis all samples revealed CeO2 phase, but additional phase of α-Ce2O3 can only be detected by SiC and GaN with CeO2 annealed at 1150 and 1000°C, respectively. The transformation of phase might assist in the formation of IL between CeO2 and the substrate. A detailed comparison on the physical and electrical characteristics of the CeO2 gate deposited on both substrates was systematically presented. [Copyright &y& Elsevier]