Cu nuclear quadrupole resonance and far-infrared reflectance of superconducting (Y sub 1 minus y Ca sub y )Ba sub 2 Cu sub 3 O sub 6

Journal Article · Wed Nov 01 04:00:00 EST 1989 · Physical Review (Section) B: Condensed Matter; (USA)

DOI:https://doi.org/10.1103/PhysRevB.40.8878· OSTI ID:5246608

Vega, A J; Crawford, M K; McCarron, E M; Farneth, W E ^[1]

---

1. Central Research and Development Department, E. I. du Pont de Nemours 356 Company, Experimental Station, P.O. Box 80356, Wilmington, Delaware 19880-0356 (USA)

{sup 63}Cu and {sup 65}Cu nuclear-quadrupole-resonance spectra of a series of materials of composition (Y{sub 1{minus}{ital y}}Ca{sub {ital y}})Ba{sub 2}Cu{sub 3}O{sub 6+{delta}} with 0{lt}{ital y}{lt}0.5 and {delta}{much lt}1 are reported. For {ital y}{gt}0.1 these materials are superconducting with {ital T}{sub {ital c}} around 45 K. For {ital y} values below 0.25 the spectra consist of two components. One signal is identical to that of Cu(1) in YBa{sub 2}Cu{sub 3}O{sub 6}, showing that the chain sites are not affected by the hole doping that accompanies substitution of Ca for Y. The other signal, which can be assigned to Cu(2) sites, is identical for all superconducting samples in the series and is not observed when {ital y}{lt}0.1. Relaxation times indicate that the Cu(1) nuclei are in insulating environments, while the Cu(2) sites are conducting. Thus the conductivity is highly anisotropic. This is also demonstrated by far-infrared reflectance spectra. As Ca is added to YBa{sub 2}Cu{sub 3}O{sub 6}, there is a gradual decrease in the strength of the {ital E}{sub {ital u}} ({ital ab} plane) modes due to free-carrier screening. The {ital A}{sub 2{ital u}} ({ital c}-axis) modes, on the other hand, remain unscreened at low frequencies.

• OSTI ID: 5246608
• Journal Information: Physical Review (Section) B: Condensed Matter; (USA), Journal Name: Physical Review (Section) B: Condensed Matter; (USA) Vol. 40:13; ISSN PRBMD; ISSN 0163-1829
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360204* -- Ceramics
Cermets
& Refractories-- Physical Properties
656100 -- Condensed Matter Physics-- Superconductivity
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ALKALINE EARTH METAL COMPOUNDS
ANISOTROPY
BARIUM COMPOUNDS
BARIUM OXIDES
CALCIUM COMPOUNDS
CALCIUM OXIDES
CHALCOGENIDES
COPPER 63
COPPER 65
COPPER COMPOUNDS
COPPER ISOTOPES
COPPER OXIDES
DATA
ELECTROMAGNETIC RADIATION
EXPERIMENTAL DATA
FAR INFRARED RADIATION
INFORMATION
INFRARED RADIATION
INTERMEDIATE MASS NUCLEI
ISOTOPES
NUCLEAR QUADRUPOLE RESONANCE
NUCLEI
NUMERICAL DATA
ODD-EVEN NUCLEI
OPTICAL PROPERTIES
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
RADIATIONS
RELAXATION TIME
RESONANCE
SPECTRAL REFLECTANCE
STABLE ISOTOPES
SUPERCONDUCTORS
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENT COMPOUNDS
TRANSITION TEMPERATURE
YTTRIUM COMPOUNDS
YTTRIUM OXIDES