Superconductivity in Pr- and Ce-doped Bi2CaSr2Cu2Oy systems

V. P. S. Awana; S. K. Agarwal; A. V. Narlikar; M. P. Das

doi:10.1103/PhysRevB.48.1211

← Back to search

Superconductivity in Pr- and Ce-doped Bi2CaSr2Cu2Oy systems

V. P. S. Awana, S. K. Agarwal, A. V. Narlikar, M. P. Das

DOI 10.1103/PhysRevB.48.1211 · Physical Review B

T1

Active bibliographic source — not scientific approval

Bibliographic access preserves source history; it does not approve extracted materials or validate reported claims. Review warnings on each occurrence separately.

Abstract

We report here a systematic study of Pr and Ce doping (at the Ca site) in Bi2CaSr2Cu2Oy. For both Pr and Ce substitutions Tc decreases with the dopant concentration. Results are interpreted in terms of the hole filling due to aliovalent substitution in the system. At a higher doping level a metal-insulator transition, is observed. Near the transition the localization length (α−1) is calculated and the possibility of having local pairs in the insulating phase is invoked. Around the transition region a dimensional changeover from two to three dimensions is observed in the variable-range hopping (VRH) regime and its consequence on superconductivity is discussed. The lattice parameters have been estimated through x-ray diffractometry and the possibility of Pr and Ce existing in more than the 3+ oxidation state in the system is inferred. Results are also compared with the existing data on other rare-earth dopings (at the Ca site) in the same system.

Source-reported materials — not catalogue approval

Formula	Reported Tc (K)	Pressure (GPa)	Type
Bi2Ca1-xPrxSr2Cu2O8 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	—	Pressure not reported	unknown
Bi2Ca1-xCexSr2Cu2O8 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	—	Pressure not reported	unknown