Improvement in Crystal Orientation and In-plane Alignment of La-doped YBCO Thin Film on BaZrO3-buffered MgO Substrate

2005 ◽  
Vol 20 (6) ◽  
pp. 1529-1535 ◽  
Author(s):  
Ai Kamitani ◽  
S. Adachi ◽  
H. Wakana ◽  
K. Tanabe

Y0.9Ba1.9La0.2Cu3Oy (La-YBCO) thin films were prepared by an off-axis magnetron sputtering method on MgO substrates with and without a BaZrO3 buffer layer. Insertion of BaZrO3 buffer layer was effective for obtaining La-YBCO films with pure c-axis orientation and in-plane alignment at low temperatures below 600 °C. We prepared La-YBCO thin films on BaZrO3-buffered MgO substrates using a temperature-gradient method, in which a template La-YBCO layer was first deposited at 600 °C, and then the temperature was continuously raised to 700 °C. By this method, La-YBCO thin films with improved crystallinity were successfully prepared. It was also proved that the insertion of the BaZrO3 buffer layer enables us to prepare high-quality La-YBCO films with high reproducibility.

1994 ◽  
Vol 341 ◽  
Author(s):  
Gun Yong Sung ◽  
Jeong Dae Suh ◽  
Sahn Nahm

AbstractAn a-axis oriented YBa2Cu3O7-x (YBCO) thin film exhibiting zero resistance at 83 K and critical current density of 7.9x103 A/cm2 at 62 K was obtained on an 180 nm - thick PrBa2Cu3 O7-xx(PBCO) buffered SrTiO3(100) substrate by two step pulsed laser deposition (PLD). The volume fraction of a-axis orientation and the crystallinity(Xmin) of the 150 nm-thick YBCO thin films were increased with increasing the thickness of PBCO buffer layer, which was varied friom 0 nm to 180 nm. It is concluded that the thickness of PBCO buffer layer is one of the important parameters to control the structural and superconducting properties of the a-axis oriented YBCO thin films using the PBCO buffer layers.


2013 ◽  
Vol 1579 ◽  
Author(s):  
Pieter Vermeir ◽  
Jonas Feys ◽  
Glenn Pollefeyt ◽  
Bram Verslyppe ◽  
Asha De Brabandere ◽  
...  

ABSTRACTChemical solution deposition techniques are a very competitive low cost method to achieve coated conductors. Recently, fluorine-free CSD methods have made a great progress for the preparation of YBCO thin films and became a sustainable alternative for the well-known trifluoroacetate CSD approach. By elucidating the reaction mechanism behind this new approach, finally giving an answer to the question why it is possible to fabricate YBCO films without TFA, different processing routes were discovered giving rise to high superconducting YBCO films (>1MA.cm-2). Each route has it's own benefits. One specific route offers the opportunity to tune the crystallographic orientation. By changing one process parameter, a shift from complete c-axis to complete a-axis orientation is observed. This can be very useful for e.g. Josephson Junctions.We particularly investigated the fundamental reaction mechanism of each reaction route, with the focus on the corresponding barium compound. Although good superconducting properties are obtained, still one major drawback limits industrial implementation: thickness. It is observed that a critical thickness of ∼500 nm eliminates the superconducting properties. Therefore, this paper gives a summary of all progress made regarding to fluorine-free water-based CSD YBCO thin films with emphasis on the possibility to control the crystallization rate.


1992 ◽  
Vol 285 ◽  
Author(s):  
P. Tiwari ◽  
T. Zheleva ◽  
J. Narayan

ABSTRACTWe have prepared high-quality superconducting YBa2Cu3O7−δ (YBCO) thin films on Si(100) with TiN as a buffer layer using in-situ multitarget deposition system. Both TiN and YBCO thin films were deposited sequentially by KrF excitner laser ( λ = 248 nm ) at substrate temperature of 650°C. Thin films were characterized using X-ray diffraction (XRD), four-point-probe ac resistivity, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Rutherford backscattering (RBS). The TiN buffer layer was epitaxial and the epitaxial relationship was found to be cube on cube with <100> TiN // <100> Si. YBCO thin films on Si with TiN buffer layer showed the transition temperature of 90–92K with Tco (zero resistance temperature) of ∼84K. We have found that the quality of the buffer layer is very important in determining the superconducting transition temperature of the thin film. The effects of processing parameters and the correlation of microstructural features with superconducting properties are discussed indetail.


1999 ◽  
Vol 9 (2) ◽  
pp. 1645-1648 ◽  
Author(s):  
H. Shimakage ◽  
A. Kawakami ◽  
Z. Wang

1993 ◽  
Vol 07 (27) ◽  
pp. 1741-1746
Author(s):  
S.F. XU ◽  
Y.J. TIAN ◽  
H.B. LÜ ◽  
Y.L. ZHOU ◽  
Z.H. CHEN ◽  
...  

We have successfully fabricated high-quality YBa 2 Cu 3 O 7−x (YBCO) thin films grown on sapphire with epitaxial Yttria-Stabilized ZrO 2 (YSZ) buffer layer by pulsed laser deposition. X-ray diffraction and Auger depth profile were used to characterize these thin films. The values of zero-resistance temperature Tco and critical current density J c (at 77 K) of c-axis oriented YBCO thin film with 500 Å-YSZ buffer layer were 91 K and 2.2×106 A/cm 2, respectively. The Auger depth profile showed that no obvious diffusion occurred between the buffer layer and the YBCO film. The influence of substrate temperature and thickness of buffer layer has been investigated.


1996 ◽  
Vol 260 (1-2) ◽  
pp. 111-116 ◽  
Author(s):  
V. Boffa ◽  
T. Petrisor ◽  
L. Ciontea ◽  
U. Gambardella ◽  
S. Barbanera

2000 ◽  
Vol 14 (09) ◽  
pp. 1007-1016
Author(s):  
Z. MORI ◽  
T. NAKAGAMA ◽  
S. HIGO ◽  
T. DOI ◽  
S. KOBA ◽  
...  

SrTiO 3 (STO) thin film was prepared on single crystal MgO (100) substrate by rf magnetron sputtering as a buffer layer of superconducting thin film. Sputtering conditions influence to the structural property were investigated. Highly epitaxial a-axis oriented STO thin film with extremely smooth surface was obtained by optimizing the sputtering parameters. YBa 2 Cu 3 O 7-δ (YBCO) thin film with critical temperature (T c ) of 89.8 K was obtained on STO buffer. Surface morphology of YBCO thin film was also improved. The effects of STO buffer were discussed in comparison with YBCO thin films on MgO substrate.


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