Observation of the Josephson plasma reflectivity edge in the infrared region in Bi-based superconducting cuprates

Citation
T. Motohashi et al., Observation of the Josephson plasma reflectivity edge in the infrared region in Bi-based superconducting cuprates, PHYS REV B, 61(14), 2000, pp. R9269-R9272
Citations number
22
Categorie Soggetti
Apllied Physucs/Condensed Matter/Materiales Science
Journal title
PHYSICAL REVIEW B
ISSN journal
10980121 → ACNP
Volume
61
Issue
14
Year of publication
2000
Pages
R9269 - R9272
Database
ISI
SICI code
1098-0121(20000401)61:14<R9269:OOTJPR>2.0.ZU;2-S
Abstract
The far-infrared c-axis optical reflectivity spectra of a heavily Pb-doped Bi2212, Bi1.6Pb0.6Sr1.8CuCu2Oy, single crystal (T-c=65 K) were measured in the superconducting state. The crystal was found to be carrier overdoped as the optical phonons are weakly screened by the electronic excitations in t he far-infrared region. Below T-c, a sharp reflectivity edge was observed, corresponding to the appearance of the Josephson plasma in the superconduct ing state. The plasma edge frequency reached 40 cm(-1) at 8 K, which is com parable with that observed for other cuprates with much less anisotropy. Th e c-axis penetration depth lambda(c) = 12.6 mu m was estimated from the uns creened plasma frequency w(ps)(c)=126.2 cm(-1). This lambda(c) value is one order of magnitude smaller than that of the optimally doped pure Bi2212, r eflecting a drastic enhancement of the interlayer coupling in Pb-doped Bi22 12.