High pressure-high temperature effect on melt-textured YBa2Cu3O7-δ high temperature superconductive material

• Published in: Journal of materials science 2000-01, Vol.35 (7), p.1607-1613
• Main Authors: PRIKHNA, T. A, GAWALEK, W, SANDIUMENGE, F, MOSHCHIL, V. E, MELNIKOV, V. S, DUB, S. N, HABISREUTHER, T, SURZHENKO, A. B, NAGORNY, P. A
• Format: Article
• Language: English
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Contact pressure; Critical current density; Critical currents; Cuprates superconductors (high tc and insulating parent compounds); Defects and impurities in crystals; microstructure; Diamond pyramid hardness; Dislocation density; Domains; Exact sciences and technology; High temperature; High temperature effects; High-Tc compounds; Materials science; Physics; Pressure effects; Properties of type I and type II superconductors; Stacking faults; Structure of solids and liquids; crystallography; Superconductivity; Superconductors; Temperature effects; Y-based cuprates; YBCO superconductors; Zirconium dioxide
• ISSN: 0022-2461; 1573-4803
• DOI: 10.1023/A:1004735309435

High pressure-high temperature (HP-HT) treatment of melt-textured YBa2Cu3O7 − δ at 2 GPa, and in the 800–950 °C pressure-temperature range for 15–30 min in contact with monoclinic pre-annealed zirconia induces: (1) the increase of the material density from 5.7 to 6.3 g/cm3 (by 9%), (2) the increase of critical current density in the direction of c-axis of YBa2Cu3O7 − δ grains from 3–3.5 × 103 up to 7 × 103 A/cm2 (in the self-field at 77 K) while in the ab-plane it remains unchanged (104 A/cm2), (3) the increase of Vickers microhardness from 3.95 up to 5.3 GPa (estimated under the 4.91-N load). The increase in dislocation density in the (001) planes of HP-HT treated YBa2Cu3O7 − δ grains from 108 up to 1012 cm−2 may be one of the reasons of the increase in critical current density. The spaces between twin domains in YBa2Cu3O7 − δ before treatment were 100–150 nm. Completely detwinned wide areas or regions, where each second twin domain was narrowed to approximately 20 nm or tapered down to zero thickness within the first domain and the disappearance of 1/6 〈 301〉 stacking faults have been observed in the treated samples.