Singh, H. K. and Kataria, N. D. and Srivastava, O. N. (2006) Optimized synthesis and improved transport properties of Cd-doped Tl-2223 films. Journal of the Korean Physical Society, 48 (SI). pp. 1159-1162. ISSN 0374-4884

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Abstract

We present an investigation of the effect of cadmium (Cd) doping on the structural phase evolution, microstructural features, and superconducting properties of Tl bearing high temperature superconducting films. These films were grown by incorporating thallium into precursor films having a nominal composition Ba2Ca2CdxCu3Oy (x = 0.0, 0.1, 0.2, 0.3 and 0.4) and deposited on single-crystal MgO(100) substrates by using ultrasonic spray pyrolysis. For thallium incorporation, the precursor films were annealed for two hours in presence of a Tl source, which was an un-reacted pellet of nominal composition Tl2.05Ba2Ca2Cu3Oz, in a evacuated (10(-5) Torr) and sealed silica tube at 890 degrees C. The structural characterization reveals that the films are polycrystalline and predominantly c-axis oriented and that around a Cd content of x >= 0.2 the films are single phase 2223. For these highly textured polycrystalline films, T-c (R = 0) is measured to be 118 K, 120 K, 124 K, 121 K and 116 K for Cd contents of x = 0.0, 0.1, 0.2, 0.3, and 0.4. respectively. The self-field critical current density (J(c)) values are found to be (at 77K) 6.85 x 10(4) A/cm(2), 7.98 x 10(4) A/cm(2), 1.12 x 10(5) A/cm(2), 8.2 x 10(4) A/cm(2) and 3.0 x 10(4) A/cm(2) for x = 0.0. 0.1; 0.2; 0.3, and 0.4, respectively. The films grown in the present study show a decrease in T-c by 5 K to 11 K on oxygen annealing. This shows that the as-grown films are almost optimally doped. At lower Cd concentrations, the microstructural characteristics, as evaluated by using SEM, reveal the occurrence of spiral growth features in the surface morphology of these films, and these spiral features disappear at higher values of x. The critical current density exhibits a strong dependence on the Cd-induced morphological variations.

Item Type:	Article
Additional Information:	Copyright for this article belongs to M/s Springer Verlag.
Subjects:	Physics
Divisions:	UNSPECIFIED
Depositing User:	Users 27 not found.
Date Deposited:	11 May 2018 08:21
Last Modified:	11 May 2018 08:21
URI:	http://npl.csircentral.net/id/eprint/2524

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