Substitution of chromium for univalent copper in superconducting Pb{sub 2}Sr{sub 2}(Ca, Y)Cu{sub 3}O{sub 8-{delta}}
Journal Article
·
· Journal of Solid State Chemistry
- ISMRA et Universite de Caen (France); and others
Following considerations of geometry and the similarity between chromate and carbonate groups in terms of size and charge, the authors have investigated the possibility of replacing the two-coordinate Cu{sup I} in superconducting lead cuprates of the general formula Pb{sub 2}Sr{sub 2}(Ca, Y)Cu{sub 3}O{sub 8} by Cr. A high-resolution electron microscopy study coupled with energy dispersive X-ray analysis on small crystals of the title phases suggests that between 10 and 15% of the Cu{sup 1} can be replaced by Cr. While from the present structural study using HRTEM and Rietveld refinement of X-ray powder data the authors are unable to precisely obtain the oxidation state and oxygen coordination of Cr, the authors suggest in analogy with Cr substitution in other similar cuprates that in the title phases Cu{sup I}O{sub 2} rods are partially replaced by tetrahedral CrO{sub 4}{sup 2-} groups. Infrared spectroscopy supports the presence of CrO{sub 4}{sup 2-} groups. The phases Pb{sub 1.75}Sr{sub 2}Ca{sub 0.2}Y{sub 0.8}Cu{sub 3}O{sub 8-{delta}} and Pb{sub 1.75}Sr{sub 2}Ca{sub 0.2}Y{sub 0.8}Cu{sub 2.85}Cr{sub 0.15}O{sub 8-{delta}} are superconducting as-prepared, but the substitution of Cr for Cu{sup I} results in a decrease of the T{sub C} as well as the superconducting volume fraction.
- OSTI ID:
- 555035
- Journal Information:
- Journal of Solid State Chemistry, Journal Name: Journal of Solid State Chemistry Journal Issue: 1 Vol. 127; ISSN 0022-4596; ISSN JSSCBI
- Country of Publication:
- United States
- Language:
- English
Similar Records
A new series of mercury-based high Tc superconductors (Hg, W)Sr{sub 2}(Y{sub 1-x}Ca{sub x})Cu{sub 2}O{sub 6+{sigma}}
Enhancement of the superconducting transition temperature of TlSr sub 2 CaCu sub 2 O sub 7 by yttrium and vanadium substitutions
Two-zone annealing of Tl[sub 0. 5]Pb[sub 0. 5](Sr[sub 0. 8]Ba[sub 0. 2])[sub 2]Ca[sub 2]Cu[sub 3]O[sub [ital y]]
Journal Article
·
Wed Jan 31 23:00:00 EST 1996
· Journal of Superconductivity
·
OSTI ID:269734
Enhancement of the superconducting transition temperature of TlSr sub 2 CaCu sub 2 O sub 7 by yttrium and vanadium substitutions
Journal Article
·
Sun Mar 31 23:00:00 EST 1991
· Journal of Solid State Chemistry; (USA)
·
OSTI ID:5689303
Two-zone annealing of Tl[sub 0. 5]Pb[sub 0. 5](Sr[sub 0. 8]Ba[sub 0. 2])[sub 2]Ca[sub 2]Cu[sub 3]O[sub [ital y]]
Journal Article
·
Sat Oct 01 00:00:00 EDT 1994
· Journal of Materials Research; (United States)
·
OSTI ID:7018585