Hole concentration and Tc in Tl sub 2 minus y Ba sub 2 Ca sub 1 minus z Y sub z Cu sub 2 O sub 8 minus x

Journal Article · Mon Jun 01 00:00:00 EDT 1992 · Journal of Solid State Chemistry; (United States)

DOI:https://doi.org/10.1016/S0022-4596(05)80244-0· OSTI ID:6998901

Paranthaman, M; Manthiram, A; Goodenough, J B ^[1]

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1. Univ. of Texas, Austin (United States)

The p-type copper-oxide superconductors all exhibit a maximum value of {Tc} at a saturation hole concentration p{sub s} per Cu atom in the superconductive CuO{sub 2} sheets. The maximum value of {Tc} varies from one structure type to another; it is not clear how p{sub s} varies. After a brief review of this problem, the hole concentration in the system Tl{sub 2{minus}y}Ba{sub 2}Ca{sub 1{minus}z}Y{sub z}Cu{sub 2}O{sub 8{minus}x}, 0 {le} z {le} 0.4, is determined with the assumption that the number of Tl-6s electrons per Cu atom does not vary appreciably with z on going from an antiferromagnetic semiconductor (z = 0.3) to a superconductor with {Tc} = 94 K (z = 0.0). A p{sub s} {approx} 0.17 {plus minus} 0.02 per Cu atom and a {Tc} {approx} (370p + 35 {plus minus} 7) K are obtained. The defects in the Tl{sub 2{minus}y}O{sub 2{minus}x} layer apparently trap out the Tl-6s electrons, probably at Tl(I) species, so the Tl-6s electrons contribute little to the electrical conductivity and the Seebeck coefficient, which were measured in sintered pelletized powders. An important expansion of the lattice a-parameter is noted on passing from the superconductive phase at z = 0.2 with p = 0.10 {plus minus} 0.02 and {Tc} = 72 K to a semiconductive phase at z = 0.3 having, the authors assume, a p = 0.02 {plus minus} 0.02.

• OSTI ID: 6998901
• Journal Information: Journal of Solid State Chemistry; (United States), Journal Name: Journal of Solid State Chemistry; (United States) Vol. 98:2; ISSN JSSCB; ISSN 0022-4596
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360207 -- Ceramics
Cermets
& Refractories-- Superconducting Properties-- (1992-)
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
ALKALINE EARTH METAL COMPOUNDS
BARIUM COMPOUNDS
BARIUM OXIDES
CALCIUM COMPOUNDS
CALCIUM OXIDES
CHALCOGENIDES
COPPER COMPOUNDS
COPPER OXIDES
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
HOLES
LATTICE PARAMETERS
MATERIALS
OXIDES
OXYGEN COMPOUNDS
P-TYPE CONDUCTORS
PHYSICAL PROPERTIES
SEEBECK EFFECT
SEMICONDUCTOR MATERIALS
SUPERCONDUCTORS
TEMPERATURE DEPENDENCE
TEMPERATURE RANGE
TEMPERATURE RANGE 0000-0013 K
TEMPERATURE RANGE 0013-0065 K
TEMPERATURE RANGE 0065-0273 K
TEMPERATURE RANGE 0273-0400 K
THALLIUM COMPOUNDS
THALLIUM OXIDES
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENT COMPOUNDS
TRANSITION TEMPERATURE
YTTRIUM COMPOUNDS
YTTRIUM OXIDES