Stoichiometric effects in epitaxial Ba2−xY1−yCu3−zO7−δ thin films on LaAlO3(100)

1990 ◽  
Vol 5 (12) ◽  
pp. 2797-2801 ◽  
Author(s):  
Douglas J. Carlson ◽  
Michael P. Siegal ◽  
Julia M. Phillips ◽  
T. H. Tiefel ◽  
J. H. Marshall
Keyword(s):  
Thin Films ◽  
Critical Temperature ◽  
Surface Morphology ◽  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Superconducting Transition ◽  
Transition Width ◽  
Composition Control ◽  
Order Of Magnitude

Stoichiometric deviations of up to ±5% in Ba2YCu3O7−δ, thin films grown by coevaporation on LaAlO3(100) substrates are found to cause (1) a decrease of the critical current density (Jc) of up to an order of magnitude, (2) a depression of the critical temperature (Tc) and a broadening of the superconducting transition width (ΔT), (3) a deterioration of the surface morphology, and (4) a decrease in the crystallinity of the films. The data indicate that composition deviations of greater than ±1% result in degradation of film quality. These findings have significant implications for the degree of composition control required during deposition to produce films with optimized properties.

Characterization of superconducting SmBa2Cu3O7 films grown by pulsed laser deposition

2002 ◽  
Vol 17 (10) ◽  
pp. 2599-2603 ◽  
Author(s):  
Q. X. Jia ◽  
S. R. Foltyn ◽  
J. Y. Coulter ◽  
J. F. Smith ◽  
M. P. Maley
Keyword(s):  
Transition Temperature ◽  
Critical Current Density ◽  
Pulsed Laser Deposition ◽  
Critical Current ◽  
Current Density ◽  
Deposition Temperature ◽  
Pulsed Laser ◽  
Laser Deposition ◽  
Superconducting Transition ◽  
Transition Width

We have investigated epitaxial superconducting SmBa2Cu3O7 (Sm123) films grown by pulsed-laser deposition on single-crystal SrTiO3 substrates. The deposition temperature plays an important role in determining the superconducting properties of Sm123 films. The superconducting transition temperature increases with the deposition temperature whereas the transition width decreases at deposition temperatures in the range of 700–875 °C. A Sm123 film deposited at 850 °C exhibits a transition temperature above 93 K with a transition width less than 0.5 K. Even though Sm123 films exhibit a higher transition temperature than Yba2Cu3O7 (Y123), the Sm123 shows lower critical current density at liquid-nitrogen temperature. The nominal critical current density of Sm123 film is less than 1 MA/cm2 at 75.4 K. Nevertheless, the Sm123 films have less anisotropy and stronger pinning characteristics compared to Y123. They are also much smoother with fewer particulates, as revealed by scanning electron microscopy.

AC SUSCEPTIBILITY OF YBCO SUPERCONDUCTING THIN FILMS

2006 ◽  
Vol 20 (15) ◽  
pp. 923-929
Author(s):  
C. SBÂRCIOG ◽  
T. R. REDAC ◽  
I. GR. DEAC
Keyword(s):  
Thin Films ◽  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Ac Susceptibility ◽  
Superconducting Thin Films ◽  
Superconducting Transition ◽  
Susceptibility Data ◽  
Complex Susceptibility ◽  
Intergranular Critical Current Density

Ca -doped (x = 0.00, 0.07 and 0.20) epitaxial Y 1-x Ca x Ba 2 Cu 3 O 7-δ thin films were prepared on SrTiO 3 (100) by PLD technique. The superconducting transition temperature is found to decrease with increasing Ca content. The AC-susceptibility data were used to determine the intergranular critical current density, when varying the field amplitude H AC . The temperature dependence of critical current density was determined from the imaginary part of the complex susceptibility, χ′′(T), using Xing's relation. The results were analyzed in terms of superconductor-insulator-superconductor (SIS) and superconductor-normal-superconductor (SNS) type models.

INDUCTIVE CHARACTERIZATION OF SUPERCONDUCTING NANO-ENGINEERED ARTIFICIAL CUPRATES

2003 ◽  
Vol 17 (04n06) ◽  
pp. 393-399
Author(s):  
P. G. MEDAGLIA ◽  
P. ORGIANI ◽  
C. ARUTA ◽  
G. BALESTRINO ◽  
A. TEBANO
Keyword(s):  
High Temperature ◽  
Critical Temperature ◽  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Pulsed Laser ◽  
Laser Deposition ◽  
Superconducting Transition ◽  
Engineered Structures

Ultrathin artificial high temperature superconducting structures were grown by pulsed laser deposition stacking in sequence epitaxial layers of ( Ba 0.9 Nd 0.1) CuO 2+x and CaCuO2. Critical temperature Tc and critical current density Jc for such nano-engineered structures consisting of a single (CaCuO2) block sandwiched between two ( Ba 0.9 Nd 0.1) CuO 2+x charge reservoir blocks were measured inductively. The onset of superconducting transition is higher than 50 K. The purely intralayer critical current density was measured at 4.2 K and resulted to be larger than 108 A/cm2.

scholarly journals О возможности изготовления мостиков YBCO с совершенной поверхностью, критической температурой более 88 K и плотностью критического тока до 5·10-=SUP=-6-=/SUP=- A/cm-=SUP=-2-=/SUP=-

2020 ◽  
Vol 62 (9) ◽  
pp. 1398
Author(s):  
Д.В. Мастеров ◽  
С.А. Павлов ◽  
А.Е. Парафин ◽  
Е.В. Скороходов
Keyword(s):  
Critical Temperature ◽  
Surface Morphology ◽  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Growth Process ◽  
Ybco Films ◽  
Basic Parameters ◽  
Critical Current Density Jc ◽  
Electrophysical Parameters

In the fabrication of YBCO structures by traditional methods, as a rule, some compromise is reached, namely, films with acceptable morphology are used, but with reduced electrophysical parameters. In this paper, it is shown that YBCO bridges up to 4 microns wide with perfect surface morphology, i.e. free from defects, with a critical current density Jc ≥ 3106 A/cm2 at a temperature T = 77 K and a critical temperature Tс ≥ 88 K. can be obtained using the preliminary topology mask method. Moreover, the perfect morphology of the bridge surface, the values of the critical current density and the critical temperature are preserved even after repeated (additional) deposition of the YBCO layer on the structure with the preliminary topology mask. Based on the results obtained in a series of fifteen samples, it is concluded that, in contrast to the electrophysical characteristics, it is not enough to fix the standard (basic) parameters of the growth process for the stable implementation of the perfect surface morphology of YBCO films.

scholarly journals GROWTH OF GdBa2Cu3Oy FILMS PREPARED BY BaF2 PROCESS WITHOUT WATER VAPOR

2007 ◽  
Vol 21 (21) ◽  
pp. 1377-1382 ◽  
Author(s):  
R. KITA ◽  
T. NAKAMURA ◽  
A. ICHINOSE ◽  
O. MIURA ◽  
K. MATSUMOTO ◽  
...  
Keyword(s):  
Thin Films ◽  
Water Vapor ◽  
Surface Morphology ◽  
Critical Current Density ◽  
Film Thickness ◽  
Heating Rate ◽  
Critical Current ◽  
Current Density ◽  
Ex Situ

We have investigated the influences of the heating rate and film thickness on the growth of GdBa 2 Cu 3 O y (GBCO) thin films prepared by the BaF 2ex-situ process without water vapor. Critical current density (J c ) and surface morphology of the GBCO films were improved by increasing the heating rate during growth from 30 to 50°C/min. The GBCO films prepared by the heating rate of 50°C/min had the maximum J c of 2.1 MA/cm2. The J c value of the GBCO films was about 2 MA/cm2 up to 200 nm, and decreased to 0.92 MA/cm2 at 400 nm.

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