Accession Number:

ADA561600

Title:

Optimization of Minute Doping of Y1-xRExBa2Cu3O7-delta Thin Films with RE = Tb and Nd (Postprint)

Descriptive Note:

Conference paper

Corporate Author:

AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH PROPULSION DIR/POWER DIV/MECHANICAL ENERGY CONVERSION BRANCH

Personal Author(s):

• Reichart, J. N.
• Thomas, E. L.
• Haugan, T. J.
• Ruter-Schoppman, B. M.
• Barnes, P. N.
• Song, X.

Report Date:

2010-01-01

Pagination or Media Count:

8.0

Abstract:

Doping of YBa2Cu3O7-delta YBCO has become an effective means of increasing the flux pinning and critical current densities Jsub c in thin film superconductors, while maintaining the transition temperature Tsub c. In previous research efforts, our group showed that doping Y1-xRExBCO with typically deleterious rare earth RE elements can be used to improve the films current density via flux pinning when the x molar additions are less than 1. However, data was only presented for different orders of magnitude x 0.1, 1.0, 10 without consideration of optimization. The research presented here demonstrates that the deleterious RE elements can differ greatly in how broad the range of optimal doping concentration is, in addition to the relative doping concentration. Rare-earth elements Nd and Tb were compared due to the difference in degradation mechanisms Nd additions results in Ba site substitution and Tb123 exhibits poor phase formation. Thin films of Nd and Tb doped YBCO films were grown by pulsed laser deposition PLD using standard deposition parameters for plain YBCO. The compositions studied were Y1-xRExBCO where x was varied from 0.0001 to 0.025 for Nd and 0.005 to 0.015 for Tb. Targets for PLD were prepared using solid state reaction and sintering procedures. All films were characterized for Jsub c and Tsub c by vibrating sample magnetometry. Data for Jsub cH,T and Tsub c were compared to undoped YBCO films processed under the same conditions. The results show a measurable increase in flux pinning for both different concentrations and range of Nd and Tb doping, with little decrease in Tsub c.

Descriptors:

• *DOPING
• *THIN FILMS
• CRITICAL TEMPERATURE
• CURRENT DENSITY
• DEGRADATION
• DEPOSITION
• OPTIMIZATION
• RARE EARTH ELEMENTS
• SUPERCONDUCTORS
• TRANSITION TEMPERATURE

Subject Categories:

• Electricity and Magnetism

Distribution Statement:

APPROVED FOR PUBLIC RELEASE