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李美亚, BMa, MLi, B L Fisher and U Balachandran
Supercond. Sci. Technol. 15(2002)1083-1087,-0001,():
-1年11月30日
Biaxially textured yttria-stabilized zirconia (YSZ) films were grown on mechanically polished Hastelloy C276 (HC) substrates by ion-beamassisted deposition and electron-beam evaporation. The surface root-mean-square (RMS) roughness of the polished HC substrates was ≈3 nm, as measured by atomic force microscopy (AFM). A water-cooled sample stage was used to hold the substrate temperature below 100◦C during deposition. RMS roughness of≈3.3 nm was measured on the deposited YSZ films by AFM. X-ray pole figures were conducted for texture analysis; in-plane texture measured from YSZ (111) φ-scan FWHM was 13.2℃ and out-of-plane texture from the YSZ (002) ω-scan FWHM was 7.7℃. An≈10 nm thick CeO2 buffer layer was deposited on the YSZ film at 800℃ before YBCO films were ablated by pulsed laser deposition at 780℃ in a 250 mTorr flowing oxygen environment. Good in-plane texture with FWHM≈7℃was observed in YBCO films. Tc=90K, with sharp transition, and transport Jc of≈2.2 ×106 A cm−2 were observed in a 0.5μm thick, 5mmwide, and 1cm long sample at 77K in self-field.
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李美亚, Meiya Lia, *, B. Mab, R.E. Koritalab, B.L. Fisherb, Xingzhong Zhaoa, V.A. Maronic, S.E. Dorrisb, U. Balachandranb
Solid State Communications 131(2004)101-105,-0001,():
-1年11月30日
Biaxially textured YBa2Cu3O72x (YBCO) films were grown on non-textured metal substrates with inclined-substratedeposited(ISD) MgO as template. The biaxial texture feature of the films was examined by X-ray pole-figure analysis, f-scan,and 2u-scan. A tilt angle of 328 of the MgO[001] with respect to the substrate normal was observed. Epitaxial growth of YBCOfilms with c-axis tilt angle of 328 with respect to the substrate normal was obtained on these substrates with SrTiO3(STO) asbuffer layer. Whereas, by choosing yttria-stabilized ZrO2 and CeO2 instead of STO as buffer layer, a c-axis untilted YBCO filmwas obtained. Higher values of Tc
A., YBCO-coated conductor, B., Inclined substrate deposition, C., X-ray pole-figure analysis, D., Orientation control
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【期刊论文】Pulsed laser deposition of YBCO thin films on IBAD-YSZ substrates
李美亚, MLi, BMa, R EKoritala, B L Fisher, K Venkataraman and U Balachandran,
Supercond. Sci. Technol. 16(2003)105-109,-0001,():
-1年11月30日
High-quality YBa2Cu3O7−x (YBCO) films were fabricated onyttria-stabilized zirconia (YSZ)-buffered Hastelloy C276 substrates bypulsed laser deposition. YSZ was grown by ion-beam-assisted deposition.A thin (≈10 nm) CeO2 layer was deposited before the deposition of YBCO.The crystalline structure and biaxial texture of the YBCO film and the bufferlayer were examined by x-ray diffraction 2θ-scan, φ-scan and pole-figureanalysis. Epitaxial growth of the YBCO film on the buffer layer wasobserved. Full width at half maximum (FWHM) value of 7.4◦ was measuredfrom the φ-scan of YBCO(103). Raman spectroscopy showedcompositional uniformity and phase integrity in the YBCO films. Surfacemorphologies of the YBCO films were examined by scanning electronmicroscopy. Comparative studies indicated that the CeO2 buffer layersignificantly improves the structural alignment and superconductingproperties of YBCO films. Tc=90K, with sharp transition, and transportJc=2.2×106 A cm−2 at 77K in zero-external field were obtained on the 0.5μm thick YBCO films. The dependence of Jc on the FWHM of theYBCO(103) φ-scan indicated that high Jc is associated with low FWHM.
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李美亚, M. Lia, *, B. Maa, R.E. Koritalaa, B.L. Fishera, K. Venkataramanb, V.A. Maronib, V. Vlasko-Vlasovc, P. Berghuisc, U. Welpc, K.E. Grayc, U. Balachandrana
Physica C 387(2003)373-381,-0001,():
-1年11月30日
Biaxially textured MgO template layer was deposited on nontextured metal substrates by inclined-substrate deposition(ISD) at a deposition rate of 24-600nm/min. c-axis untilted YBa2Cu3O7 x (YBCO) films were deposited on theseMgO-buffered substrates by pulsed laser deposition. The crystalline structures of the YBCO films and MgO layers wereexamined by X-ray pole figure analysis, X-ray/-scans, and v-scans. A tilt angle of 33 of the MgO[001] with respect tothe substrate normal and c-axis untilted YBCO films were observed, respectively. Good biaxial texture of these filmswith full-width-at-half-maximum values of 13.8 and 10.6 for the/-scans of YBCO(103) and MgO(220), respectively,were obtained. Morphologies were examined by scanning electron microscopy, which revealed a unique roof-tile featureand columnar grain growth for the ISD MgO layer. Raman spectroscopy and magneto-optical image technique werealso used to evaluate the quality of the YBCO film. An angular dependence of Jc on the direction of an applied magneticfield confirmed the c-axis untilted orientation of the YBCO films. Tc
YBCO-coated conductor, Biaxial texture, ISD, Pulsed laser deposition
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李美亚, MLi, BMa, R E Koritala, B L Fisher, S E Dorris, K Venkataraman and U Balachandran
Supercond. Sci. Technol. 15(2002)986-990,-0001,():
-1年11月30日
Fully c-axis-oriented YBCO films were directly deposited on polycrystallinesilver substrates by inclined substrate pulsed laser ablation. The orientationand microstructure of the YBCO films were characterized by x-raydiffraction 2θ-scans,Ω-scans and pole figure analysis. Surface morphologywas examined by scanning electron microscopy. Irregular-mosaic-shapedsupergrains were observed in the films. Raman spectroscopy was used toevaluate the quality of the YBCO films. The superconducting transitiontemperature (Tc) and the critical current density (Jc) of the films weredetermined by inductive and transport measurements, respectively. Tc=91K with sharp transition and Jc=2.7×105 A cm−2 at 77K in zero fieldwere obtained on a film that was 0.14μm thick, 5mm wide and 10 mmlong. This work demonstrated a promising approach to obtain high-JcYBCO films on nontextured polycrystalline silver substrate.
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