Substrate bias effects during R-F sputtering of Y-Ba-Cu-O films

1990 ◽  
Vol 5 (4) ◽  
pp. 677-679 ◽  
Author(s):  
A. J. Drehman ◽  
M. W. Dumais

Y-Ba-Cu-O films were made by R-F diode sputtering using a single oxide target. It was found that if a small negative bias is applied to the substrate, the etching associated with reactive sputtering is significantly reduced. This results in better composition control and uniformity, which are quite important for the formation of superconducting thin films. Films deposited on strontium titanate, when annealed in oxygen, become superconducting with zero resistance at 89 K.

1992 ◽  
Vol 06 (08) ◽  
pp. 477-483 ◽  
Author(s):  
QINGXIN SU ◽  
SHIFA XU ◽  
DAFU CUI ◽  
HUIBIN LU ◽  
YONGJUN TIAN ◽  
...  

High-T c superconducting thin films of YBa 2 Cu 3 O 7 were grown in-situ on (100) SrTiO 3 substrates by Nedymium:yttrium aluminum garnet [Nd:YAG] laser ablation. The effects of the substrate temperature on the transition temperature, microcrystalline structure and surface morphology of the films were discussed. Best results were obtained in the 730°–770°C range. X-ray diffraction analysis showed that these films were highly c-oriented with the c-axis perpendicular to the substrate surface. At the optimum substrate temperature, a very smooth morphology with only a few small particles were observed by scanning electron microscopy. The zero resistance temperature of these films were ≥ 90 K with a narrow transition width and the ac susceptibility measurement also gave the same result. The highest critical current density obtained at 77 K and zero magnetic field was 3.8 × 106 A/cm 2.


1993 ◽  
Vol 07 (01) ◽  
pp. 19-23 ◽  
Author(s):  
W. A. LUO ◽  
Y. Q. TANG ◽  
Y. Z. CHEN ◽  
I. N. CHAN ◽  
K. Y. CHEN ◽  
...  

In this letter, we describe results obtained via laser ablation to fabricate Tl 2 Ba 2 Ca 2 Cu 3- O 10 superconducting thin films using a two-step process. We found that the zero-resistance temperatures are up to 121 K, while the onset temperatures are up to 125 K. The T c and J c are mainly determined by a non-contact new technique for high-T c films. The typical critical current density, J c , is about 106 A/cm 2 at 77 K. X-ray diffraction showed that the superconducting thin films are nearly single 2223 phase and are highly oriented.


1988 ◽  
Vol 3 (4) ◽  
pp. 613-618 ◽  
Author(s):  
D. J. Mikalsen ◽  
R. A. Roy ◽  
D. S. Yee ◽  
S. A. Shivashankar ◽  
J. J. Cuomo

Superconducting thin films of the Bi–Sr–Ca–Cu–O system (2 and 10 kÅ) have been successfully prepared by multilayer deposition from elemental metal sources and annealed in N2/O2 mixtures. The onset of the superconducting transition is greater than 80 K with zero resistance at 74 K. The films contain primarily a Bi2(SrCaBi)3Cu2O8 + δ phase with a high degrees of (001) preferred orientation.


2000 ◽  
Vol 14 (25n27) ◽  
pp. 2731-2736 ◽  
Author(s):  
M. BINDI ◽  
F. FUSO ◽  
N. PUCCINI ◽  
E. ARIMONDO ◽  
A. TAMPIERI ◽  
...  

Correctly c-axis oriented HgBa 2 CaCu 2 O 6+δ thin films have been produced on (100) MgO single crystal substrates and characterized. Pulsed laser deposition has been exploited to deposit Hg-free Re-doped precursor which then underwent synthesis in evacuated and sealed quartz tubes. X-ray diffraction pattern of the precursor target shows the expected composition of oxides. Scanning electron microscopy analysis have been performed on the surface of the precursor film. Hg-1212 films have been analyzed by θ-2θ Bragg-Brentano X-ray diffractometry. The patterns show little contributions in composition of Hg-1223 phase. The films exhibit a transition temperature >120 K with zero-resistance at around 115 K.


1989 ◽  
Vol 169 ◽  
Author(s):  
Shinji Gohda ◽  
Yasuhiro Maeda

AbstractBi‐Sr‐Ca‐Cu‐0 superconducting thin films have been prepared on MgO substrates by a Metalorganic Chemical Vapor Deposition technique using an infrared lamp. It was found in this study that the film composition ratio could be precisely controlled by using this technique. A zero resistance at 81K was obtained for Bi1Sr1.3Ca0.9Cu1.8Ox film grown at 850°C. The critical current density of this film was 1.0xl03A/cm2 at 77K.


1987 ◽  
Vol 01 (02) ◽  
pp. 579-582
Author(s):  
Guang-yao Meng ◽  
Xian-dong Wang ◽  
Xue-jun Chen ◽  
Pei-zhen Fu ◽  
Pinghua Yang ◽  
...  

A Chemical spray deposition process with mixed nitrate solution as source was developed to prepare thin films of Ba-Y-Cu oxide on sapphire substrate. By adjusting the source composition and deposition conditions, we have successfully obtained the films in thickness of 2–15μm with essentially orthorhombic Ba2YCu3O7 phase. The films behave super conducting transition with onset above 90K and zero resistance at 68.4K to date. It is believed that the tails in the resistance transition can be improved by searching proper heat treatment and using suitable substrates such as ZrO2 and SrTiO3.


1989 ◽  
Vol 169 ◽  
Author(s):  
Ashok Kumar ◽  
L. Ganapathi ◽  
J. Narayan

AbstractWe have prepared highly textured superconducting thin films from Bi1.5pb0.5Ca3Sr2Cu4Ox (2324) on (100) YS-ZrO2 (Yttria stabilized zirconia) and Bi1.5Pb0.5Ca2Sr2Cu3°x (2223) on LaAlC-3 (100) and MgO (100) substrates at 650°C by pulsed laser ablation method.These films showed 2212 type of phase of the (BiPb)2(Ca,Sr)n+1CunO2n+4+5 family with onset transition temperature ( Tc ) ~ 110 K, confirming our earlier observations of 110 K superconductivity in a n = 2 bulk material. Thin films deposited from 2324 bulk target on YS-Z1O2 showed zero resistance temperature (Tco ) of 68 K but post annealing for one hour at 400°C in oxygen improved Tco from 68 K to 82 K. Thin films from 2223 target on LaAlO3 ( 100 ) and MgO ( 100 ) exhibited a Tco of 65 K and 74 K respectively while onset remained the same at 110 K. Further annealing at 400°C for one hour in oxygen did not show any improvement in Tco. X-ray diffraction (XRD), scanning electron microscopy (SEM) and Rutherford backscattering (RBS) channeling studies were performed on these films for correlation between crystal structure, microstructure and superconducting properties. X-ray diffraction patterns indicated 2212 type phase with a= 5.39 Å and c=30.76 Å; preferential orientation of c-axis perpendicular to the substrate was observed. The lattice parameter and x-ray diffraction patterns were found to be invariant with annealing treatments.


1990 ◽  
Vol 04 (07) ◽  
pp. 479-483 ◽  
Author(s):  
S. L. YAN ◽  
H. L. CAO ◽  
Q. X. SONG ◽  
X. M. YANG ◽  
J. YAN ◽  
...  

Superconducting thin films of Tl 2 Ca 2 Ba 2 Cu 3 O x have been prepared by dc magnetron sputtering from a pair of stoichiometric Tl-based targets onto YSZ substrates. The superconducting transition properties and the morphology of the films depend strongly on the post-annealing conditions. The zero resistance temperature for the best films we got is 117 K. X-ray diffraction analysis indicates that the annealed films with needle-like structure and terraced configuration are both highly c-axis oriented normal to the film surface.


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