1. Doping states and irreversibility fields of high-pressure-synthesized (Tl,Cu)Sr2Ca2Cu3Oy superconductors
- Author
-
Toshio Kimura, Tadashi Tatsuki, T. Shibata, K. Tanabe, Shinobu Fujihara, and Seiji Adachi
- Subjects
Superconductivity ,Materials science ,Condensed matter physics ,Annealing (metallurgy) ,Doping ,Analytical chemistry ,Energy Engineering and Power Technology ,Condensed Matter Physics ,Electronic, Optical and Magnetic Materials ,Lattice constant ,Reduced properties ,Electrical resistivity and conductivity ,High pressure ,Seebeck coefficient ,Electrical and Electronic Engineering - Abstract
The effects of Cu substitution for Tl in TlSr 2 Ca 2 Cu 3 O y superconductor were investigated. Nearly single-phase samples of Tl 1− x Cu x Sr 2 Ca 2 Cu 3 O y ( x =0.2−0.6) were successfully synthesized using a high pressure technique. The observed shrinkage in the lattice parameter a , concave ρ – T curve above T c and negative thermoelectric power near room temperature indicated that the Cu-substituted samples were over-doped. T c for the sample with x =0.4 increased from 73 to 94 K after annealing treatment in flowing argon gas. The Cu-substituted samples showed lower irreversibility field B irr as a function of reduced temperature than that of the pristine TlSr 2 Ca 2 Cu 3 O y [Physica C 324 (1999) 15].
- Published
- 2001