Crystalline characteristics and superconducting properties of Bi2212 thin films prepared by the Pechini sol–gel method: the effect of different substrates on the film growth

2015 ◽  
Vol 48 (1) ◽  
pp. 37-43 ◽  
Author(s):  
Xiaoming Lu ◽  
Xuejiao Miao ◽  
Dalu Sun ◽  
M. Babar Shahzad ◽  
Yang Qi

Bi2Sr2CaCu2O8+δ(Bi2212) superconducting thin films were prepared by the Pechini sol–gel method using nitrates as reactants. The precursor sol was deposited on LaAlO3(100) and MgO(100) single-crystal substratesviathe spin-coating method. The results revealed that the phase formation temperature region of the pure Bi2212 phase and perfectly epitaxial Bi2212 films deposited on LaAlO3substrates was significantly expanded to 8 K, indicating an improvement in crystallization of Bi2212 films. In addition, the phase formation temperature region of the pure phase andc-axis-grown Bi2212 films deposited on MgO substrates was reduced to 5 K because of the deterioration of epitaxy of Bi2212 films sintered at higher temperature. According to the investigation, theTc,onsetvalues of Bi2212 films grown on MgO substrates were about 92 K. Meanwhile, the optimalTc,onsetvalue of Bi2212 superconducting films grown on LaAlO3substrates rose to 96 K.

2008 ◽  
Vol 47-50 ◽  
pp. 625-629 ◽  
Author(s):  
X.H. Xia ◽  
J.P. Tu ◽  
J. Zhang ◽  
X.L. Wang

NiO thin films were prepared on ITO glass by a modified sol-gel method in combination with a following annealing process. The XRD results show that the film annealed at 280 °C is amorphous, while the films annealed at and above 300 °C are cubic NiO phase. The electrochromic performances of the annealed films were characterized by means of UV–vis spectroscopy and cyclic voltammetry (CV) measurements. The film annealed at 280 °C exhibits a noticeable electrochromism with a variation of transmittance up to 76 % at 550 nm. The cyclic voltammetry (CV) measurements reveal that the film annealed at higher temperature has better electrochemical reversibility.


2013 ◽  
Vol 543 ◽  
pp. 293-296 ◽  
Author(s):  
G. Plesch ◽  
A.A. Haidry ◽  
M. Gregor ◽  
P. Durina ◽  
J. Gregus ◽  
...  

TiO2thin films with a thickness of about 150 nm were deposited by spin coating method on sapphire substrate from a sol-gel system. The hydrogen sensing properties of TiO2films annealed at various temperatures were studied and correlated with their structure, optical and electrical properties. The annealing temperatures in the range of 600 800 °C lead to anatase films with a roughness in the range of 0.6 0.9 nm. Their sensitivity towards hydrogen is low. The thin films annealed at temperatures in the range 900 1000 °C consist of rutile phase and their roughness increased to 11.7 13.5 nm. They showed good hydrogen sensitivity with optimal operating temperature 200 250 °C. The structure and sensing properties of the prepared films are compared with those synthesized with magnetron sputtering. The maximum of sensitivity was measured on the thin films with diameter of the grains about 100 nm in both cases, i.e. on thin films prepared by sol-gel method as well as on thin films prepared by magnetron sputtering. The maximum sensitivity correlates with the diameter of the grains and dont depend on the allotropy of the titanium dioxide anatase or rutile.


2015 ◽  
Vol 33 (4) ◽  
pp. 732-741 ◽  
Author(s):  
Anna Adamczyk

AbstractAluminosilicate materials were obtained by sol-gel method, using different Al2O3 and SiO2 precursors in order to prepare sols based on water and organic solvents. As SiO2 precursors, Aerosil 200TM and tetraethoxysilane TEOS: Si(OC2H5)4 were applied, while DisperalTM and aluminium secondary butoxide ATSB: Al(OC4H9)3 were used for Al2O3 ones. Bulk samples were obtained by heating gels at 500 °C, 850 °C and at 1150 °C in air, while thin films were synthesized on carbon, steel and alundum (representing porous ceramics) substrates by the dip coating method. Thin films were annealed in air (steel and alundum) and in argon (carbon) at different temperatures, depending on the substrate type. The samples were synthesized as gels and coatings of the composition corresponding the that of 3Al2O3·2SiO2 mullite because of the specific valuable properties of this material. The structure of the annealed bulk samples and coatings was studied by FT-IR spectroscopy and XRD method (in standard and GID configurations). Additionally, the electron microscopy (SEM) together with EDS microanalysis were applied to describe the morphology and the chemical composition of thin films. The analysis of FT-IR spectra and X-ray diffraction patterns of bulk samples revealed the presence of γ-Al2O3 and δ-Al2O3 phases, together with the small amount of SiO2 in the particulate samples. This observation was confirmed by the bands due to vibrations of Al–O bonds occurring in γ-Al2O3 and δ-Al2O3 structures, in the range of 400 to 900 cm−1. The same phases (γ-Al2O3 and δ-Al2O) were observed in the deposited coatings, but the presence of particulate ones strongly depended on the type of Al2O3 and SiO2 precursor and on the heat treatment temperature. All thin films contained considerable amounts of amorphous phase.


2013 ◽  
Vol 46 (2) ◽  
pp. 379-386 ◽  
Author(s):  
Xiaoming Lu ◽  
Tianlin Wang ◽  
Yaming Zhang ◽  
M. Babar Shahzad ◽  
Yang Qi

Bi2Sr2CaCu2O8+δ(Bi2212) superconducting thin films were prepared by the Pechini sol–gel method using nitrates as reactants. The precursor sol was deposited on SrTiO3(001) single-crystal substratesviathe spin-coating method, and the results revealed the lowering of the Bi2212 phase-transition temperature; meanwhile the sintering time was significantly reduced. According to this investigation, the phase purity and crystallinity of Bi2212 thin films were obviously improved owing to the stable gel mechanism; theTc,onsettransition temperature value of the purec-axis Bi2212 thin films rose to about 95 K.


2018 ◽  
Vol 44 (6) ◽  
pp. 6402-6408 ◽  
Author(s):  
Pan Chen ◽  
Shuanghao Wu ◽  
Peng Li ◽  
Jiwei Zhai ◽  
Bo Shen

1994 ◽  
Vol 33 (Part 1, No. 5A) ◽  
pp. 2675-2678 ◽  
Author(s):  
Chang Jung Kim ◽  
Dae Sung Yoon ◽  
Joon Sung Lee ◽  
Chaun Gi Choi ◽  
Kwangsoo No

2005 ◽  
Vol 12 (05n06) ◽  
pp. 697-701 ◽  
Author(s):  
M. RUSOP ◽  
K. UMA ◽  
T. SOGA ◽  
T. JIMBO

The transparent c-axis oriented ZnO thin films have been prepared by sol–gel method using zinc acetate as cations source, 2-mrthoxiethanol as solvent and monoethanolamine as sol stabilizer. Film deposition was performed by dip coating technique at a withdrawal rate of 10 mm/min on quartz and silicon substrates. The effect of annealing temperature in air ambient from 100 to 800°C on the structural, optical and electrical properties of the films is discussed. ZnO films annealed with higher temperature showed an extremely sharp (002) peak in the XRD patterns, indicates increased crystallization. The optical transmittance spectra of the films is found to change with annealing temperature and showed a very good transmittance (between 80 to 90%) with the films prepared at 600°C showed highest optical transparency within the visible wavelength region. The absorption edge analysis revealed that the optical band gap is found to increase with annealing temperature up to 3.5 eV at 600°C and decreased with higher temperature. Electronic transition was found to be direct transition type. The minimum electrical resistivity of 55 Ω-cm was obtained for the films annealed at 600°C.


2011 ◽  
Vol 10 (2) ◽  
pp. 187-192 ◽  
Author(s):  
Ramona-Crina Suciu ◽  
Marcela Corina Rosu ◽  
Teofil Danut Silipas ◽  
Emil Indrea ◽  
Violeta Popescu ◽  
...  

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