Synthesis of bulk superconductors RBa sub(2)Cu sub(4)O sub(8) (R identical with Tm, Er, Ho, Y, Dy and Gd) by a simple solid-state reaction method

• Published in: Physica. C, Superconductivity Vol. 262; no. 3-4; pp. 261 - 265
• Main Authors: Tatsumi, Masakazu, Kawazoe, Makoto, Yamamoto, Seika
• Format: Journal Article
• Language: English
• Published: 01.01.1996
• ISSN: 0921-4534

Bulk superconductors of RBa sub(2)Cu sub(4)O sub(8) (R identical with Tm, Er, Ho, Y, Dy and Gd) were successfully synthesized at 1 atm oxygen pressure. The mixed starting powders (R sub(2)O sub(3), BaCO sub(3) and CuO) were pressed and pre-sintered at 900 degree C for 2 days in air or at 800 degree C for 12 h in vacuo, and then annealed in oxygen flow at the rate of 200 cm super(3)/min. Lattice constants increased and T sub(c) values decreased with increasing ionic radii of rare earth elements for the R-substituted RBa sub(2)Cu sub(4)O sub(8) system. In the case of R identical with Yb and Sm, the RBa sub(2)Cu sub(4)O sub(8) phase was not obtained in our experiments.