Preparation of Bi-2212/Ag Tapes by Electrodeposition
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Preparation of Bi-2212/Ag Tapes by Electrodeposition Jun Chen1,2 , Raghu Bhattacharya1, Ramakrishnan Padmanabhan11, 3, Richard Blaugher1 1. National Renewable Energy Laboratory, 1617 Cole Blvd, Golden, CO 80401 2. Department of Physics, Boston College, Chestnut Hill, MA 02467 3. Department of Physics, University of Colorado at Boulder, Boulder, CO 80309 ABSTRACT Bi-2212 precursor films were deposited on both sides of polycrystalline Ag tapes by electrodeposition. After a melt-solidification process in flowing oxygen atmosphere, c-axis textured Bi-2212 films with Jc( 0T, 4.2K) up to 820,000 A/ cm2 were obtained. A post annealing in flowing nitrogen at 475°C for 25 minutes increased Tc from 72 K to 92 K, and Jc(H=0T) > 17, 000A/ cm2 was observed at 60 K. No scaling behavior of the pinning force was observed, indicating more than one pinning mechanism in thus obtained Bi-2212/Ag tapes. INTRODUCTION High temperature superconducting (HTS) conductors with high critical current density are desirable for many electric power and high magnetic field applications such as transmission cables, electric generators, and high field magnets. Significant effort has been focused on the development of Bi-2212 superconducting wires and tapes due to its rapid phase formation and high critical current density in high magnetic fields at temperatures up to 30K. Several meltprocessing techniques such as powder-in-tube [1], doctor-blade [2], dip-coating [3], electroplating [4], have been explored to produce Bi-2212 tapes and wires , and recently Jc of 500,000A/cm2 at 4.2 K, 10 T has been grown by a pre-annealing and intermediate rolling (PAIR) process [5]. Because it is cheap and fast, electrodeposition is a promising method of growing HTS film. Nearly all of the oxide superconductors have been grown by this technique with promising properties [6-9]. While most of electrodeposition has been focused on the Tl system, the recent preparation of high quality Bi-2212/Ag tapes by Villard et al. attracted much attention [4]. They prepared Bi-2212 precursor films by sequential electrodeposition and obtained Jc up to 40,000A/cm2 at 77K. Recently our group developed a co-electrodeposition technique to grow high quality superconducting films [8, 9]. A significant advantage of this technique is that mixture of the constituent elements occurs at the atomic scale with submicron particle size, which significantly decreases the annealing time and improves the transport properties of superconducting films. With this technique, we have grown textured (TlBi)(SrBa)2Ca2Cu3Ox films on LAO single crystal substrates with Jc >1×106A/cm2 at 77 K [10]. In this paper, we report on the preparation of uni-axially c-axis textured Bi-2212 on polycrystalline Ag tapes by co-electrodeposition.
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EXPERIMENTAL Precursor films with a nominal composition of Bi2Sr2Ca1Cu 2.5Ox were prepared by coelectrodeposition of the constituent metals using nitrate salts dissolved in dimethyl sulfoxide (DMSO) solvent. The electrodeposition was performed in a closed-cell configuration at
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