Congxin Ren

Ion beam assisted deposition of biaxially textured YSZ thin films as buffer layers for YBCO superconducting films

Abstract Biaxially textured Yttria-Stabilized Zirconia films for use as buffer layers of YBCO superconducting films have been deposited on polycrystalline Ni Cr metallic substrates by using ion beam assisted deposition system with dual ion sources. The effects of ion bombardment on biaxial texture and growth mechanism of these films were investigated.

Electron emission suppression characteristics of molybdenum grids coated with Pt films by ion-beam-assisted deposition

Pt was deposited onto molybdenum grids by the ion-beam-assisted deposition method. The electron emission characteristics of molybdenum grids, with and without Pt, contaminated by active electron emission substances (Ba, BaO) of the cathode were measured using analogous diode method. The x-ray diffraction, energy dispersive x-ray, and x-ray photoelectron spectroscopy analyses were preformed on the surface of the molybdenum grids coated with Pt. The electron emission current from the molybdenum grid coated with a Pt film is smaller than that without the Pt film, and the mechanism for electron emission suppression of the molybdenum grid coated with the Pt film was discussed.

Control of the YSZ biaxial alignment on polycrystalline NiCr substrates by ion beam selective resputtering

(001)-oriented and in-plane aligned yttria-stabilized zirconia (YSZ) films were synthesized on polycrystalline NiCr substrates by ion beam assisted deposition (IBAD). The YSZ biaxial alignment were found to be controlled by the assisted argon ion beam bombardment. The incident angle and energy of the assisted bombarding ion beam strongly influence the alignment. The optimal alignment was obtained with the assisted ion beam bombarding at 55° incident angle and 250–500 energy. The Monte Carlo method was used to simulate the alignment formation with argon ions bombarding the zirconia crystals. Results indicated that when the energy of the bombarding ions is less than 50 eV, there is no obvious difference in the sputtering yields and the radiation damage of zirconia between different incident angles. However with the ion energy increasing, the variation increases rapidly. When the ion energy reaches 250 eV, the sputtering yields and the radiation damage of zirconia induced by Ar+ bombarding along [111] direction (54.7° from the [001]) of the zirconia are much lower than those produced by Ar+ bombarding along other directions. It can be concluded that the (001)-oriented grains are resputtered less than other grains when the assisted ions bombarding at 55° incident angle, which causes YSZ grains with (001) orientation to prevail over initial random oriented grains and form the biaxial alignment.

Homogeneity measurement of Jc of large-scale high Tc thin films

Abstract The homogeneity measurement of J c of large scale high T c thin films has been carried out by using a single-coil inductive method. The tests of HTS samples show that the measuring error of this method is less than 10%, the repeatability error is less than 5%, and the systematic error introduced in calculation is about 15%.

Channel and temperature effect on the growth of yttria-stabilized zirconia films fabricated by ion-beam-assisted deposition

Abstract Biaxially-textured yttria-stabilized zirconia (YSZ) films for use as buffer layers of YBCO superconducting films have been synthesized on NiCr metallic substrates by using ion-beam-assisted deposition (IBAD). Investigation of the growth mechanism of biaxially-textured YSZ films controlled by ion beam and the combined effect of substrate temperature and simultaneous ion bombardment on the structural property of YSZ films has been carried out in this paper.