Synthesis and characterization of the superconducting cuprates (Pb,Cu)Sr2(Y,Ca)Cu2Oz

Toshihiko Maeda; Kazuhiro Sakuyama; Shin-ichi Koriyama; H. Yamauchi; Shoji Tanaka

doi:10.1103/PhysRevB.43.7866

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Synthesis and characterization of the superconducting cuprates (Pb,Cu)Sr2(Y,Ca)Cu2Oz

Toshihiko Maeda, Kazuhiro Sakuyama, Shin-ichi Koriyama, H. Yamauchi, Shoji Tanaka

DOI 10.1103/PhysRevB.43.7866 · Physical Review B

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Abstract

Single-phase ceramics of superconducting Pb-based layered copper oxides (Pb(1+x)/2Cu(1−x)/2)Sr2 (Y1−xCax)Cu2Oz (x=0–0.35 and z≃7) are successfully synthesized in an oxidizing atmosphere. The compounds that contain appropriate amounts of Ca (x>0.2) exhibit superconductivity when annealed in air and subsequently quenched into liquid nitrogen. The superconductivity transition temperature increases with increasing x and is raised to 52 K for nearly single-phase samples with x=0.4. It is shown that, when the sample with x=0.35 is quenched, the oxygen content z decreases from 7.10 to 6.99, which is practically equal to the stoichiometric value of 7. It is shown that the length of the a axis is nearly independent of the value of x, being constant at a fixed value for each set of as-sintered and quenched samples and that the a axis of the crystal is shrunken by quenching compared with that of a crystal slowly cooled.

Source-reported materials — not catalogue approval

Formula	Reported Tc (K)	Pressure (GPa)	Type
(Pb(1+x)/2Cu(1-x)/2)Sr2(Y1-xCax)Cu2Oz Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	52	Pressure not reported	onset
Pb2Sr2(Y,Ca)Cu3O8 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	70	Pressure not reported	unknown
(Pb0.5Cu0.5)Sr2YCu2Oz Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	—	Pressure not reported	unknown
(Pb0.65Cu0.3)Sr2(Y0.7Ca0.3)Cu2Oz Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	—	Pressure not reported	unknown