• X Y Liu

      Articles written in Bulletin of Materials Science

    • Properties of Nb-doped ZnO transparent conductive thin films deposited by rf magnetron sputtering using a high quality ceramic target

      J W Xu H Wang M H Jiang X Y Liu

      More Details Abstract Fulltext PDF

      Nb-doped ZnO films with (002) orientation have been grown on glass substrates by rf magnetron sputtering followed by vacuum annealing at 400°C for 3 h. The microstructures and surface figures of the Nbdoped ZnO films were investigated with X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. And its optical and electrical properties were measured at room temperature using a four-point probe technique and 756-type spectrophotometer, respectively. X-ray diffraction (XRD) revealed that the films are highly textured along the 𝑐 axis and perpendicular to the surface of the substrate. After annealing at 400°C for 180 min under vacuum, transmittance of about 90% in visible region for Nb doped ZnO films was confirmed by the optical transmission spectra, and the low resistivity of 5.47 × 10-3 𝛺.cm was obtained.

    • Electrical properties of Sr𝑥Ba1−𝑥Fe0.6Sn0.4O3−𝜀 NTC thermistors

      C L Yuan X Y Liu J W Xu X W Zhang C R Zhou

      More Details Abstract Fulltext PDF

      Polycrystalline thermistor ceramics with the stoichiometric formula, Sr𝑥Ba1−𝑥Fe0.6Sn0.4O3−𝜀 (0.2 ≤ 𝑥 ≤ 0.8), had been prepared by a standard solid state reaction route. X-ray diffraction analysis indicates that the ceramic system remains cubic perovskite structure with a very small lattice change. The electrical properties of Sr𝑥Ba1−𝑥Fe0.6Sn0.4O3−𝜀 thermistors were studied using a digital thermometer over a wide range of 298–400 K. The thermistors showed an excellent negative temperature coefficient (NTC) thermistor behaviour. The values of resistivity at 298 K (ρ982), thermistor constant (𝐵298/358) and activation energy (𝐸a) of the Sr𝑥Ba1−𝑥Fe0.6Sn0.4O3−𝜀 thermistors, decreasing with the increase of Sr content, were in the range of 0.37–11.0 k𝛺.cm, 2466–3703 K and 0.212–0.319 eV, respectively. For the thermistors with the compositions 𝑥 = 0.2 and 0.4, the fitting equivalent circuit was composed of three RCPE elements corresponding to grain, grain boundary and ceramic–electrode interface, respectively. From the impedance plots, it was found that the fitting data showed good agreement with the experimental data. The extracted grain boundary resistance exhibited a NTC thermistor behaviour.

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    • Dr Shanti Swarup Bhatnagar for Science and Technology

      Posted on October 12, 2020

      Prof. Subi Jacob George — Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bengaluru
      Chemical Sciences 2020

      Prof. Surajit Dhara — School of Physics, University of Hyderabad, Hyderabad
      Physical Sciences 2020

    • Editorial Note on Continuous Article Publication

      Posted on July 25, 2019

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