{sup 199}Hg and {sup 63}Cu NMR in superconducting HgBa{sub 2}CuO{sub 4+{delta}} oriented powder

Journal Article · Mon Jul 01 00:00:00 EDT 1996 · Physical Review, B: Condensed Matter

DOI:https://doi.org/10.1103/PhysRevB.54.545· OSTI ID:367147

Suh, B J; Borsa, F; Sok, J; Torgeson, D R; Xu, M ^[1]; Xiong, Q ^[2]; Chu, C W ^[3]

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1. Ames Laboratory and Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011 (United States)
2. Department of Physics, High Density Electronics Center, University of Arkansas, Fayetteville, Arkansas 72701 (United States)
3. Department of Physics and the Texas Center for Superconductivity at the University of Houston, Houston, Texas 77204 (United States)

{sup 199}Hg NMR was measured in both normal and superconducting states for oriented HgBa{sub 2}CuO{sub 4+{delta}} superconducting powder with {Tc}=96 K. The large anisotropic Knight shift of {sup 199}Hg, {sup 199}K{sub ax}={minus}0.15% at room temperature, is explained by the chemical shift related to the linear Hg-O(2) bonding configuration. Both {sup 199}K{sub iso} and {sup 199}K{sub ax} decrease below {Tc} and scale linearly with each other in the whole temperature range investigated. The {sup 199}Hg Knight shift {sup 199}{ital K} slowly decreases with decreasing temperature on approaching {ital T}{sub {ital c}} in the normal state, reflecting the decrease of the uniform spin susceptibility {chi}{prime}(0,0) with lowering temperature. The {sup 199}Hg spin-echo decay can be fit by the product of a Gaussian component ({ital T}{sup {minus}1}{sub {ital G}}) and an exponential one ({ital T}{sup {minus}1}{sub {ital L}}). The Gaussian component {ital T}{sup {minus}1}{sub {ital G}} which is dominant above {ital T}{sub {ital c}}, is shown to be due mainly to an indirect nuclear interaction via the conduction electrons (holes) and is found to be directly proportional to the spin contribution ({sup 199}{ital K}{sup sp}) of the Knight shift. The exponential component {ital T}{sup {minus}1}{sub {ital L}} becomes dominant well below {ital T}{sub {ital c}} and is ascribed to the effect of thermal motion of flux lines. The {sup 199}Hg nuclear spin-lattice relaxation rate {ital T}{sup {minus}1}{sub 1} in the normal state shows a Korringa behavior well above {ital T}{sub {ital c}} with ({ital T}{sub 1}{ital T}){sup {minus}1}=0.1 sec{sup {minus}1} K{sup {minus}1}. Reduction of ({ital T}{sub 1}{ital T}){sup {minus}1} with decreasing temperature is observed starting about 10 K above {ital T}{sub {ital c}} and is consistent with the decrease of {chi}{prime}(0,0) in the normal state observed in {ital K}({ital T}) and {ital T}{sup {minus}1}{sub {ital G}}. (Abstract Truncated)

• Research Organization: Ames National Laboratory
• DOE Contract Number: W-7405-ENG-82
• OSTI ID: 367147
• Journal Information: Physical Review, B: Condensed Matter, Vol. 54, Issue 1; Other Information: PBD: Jul 1996
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
66 PHYSICS
HIGH-TC SUPERCONDUCTORS
ELECTRONIC STRUCTURE
MERCURY 199
NMR SPECTRA
COPPER 63
POWDERS
MERCURY OXIDES
BARIUM OXIDES
COPPER OXIDES
KNIGHT SHIFT
CHEMICAL SHIFT
SPIN-LATTICE RELAXATION
TEMPERATURE DEPENDENCE
TEMPERATURE RANGE 0-13 K
TEMPERATURE RANGE 13-65 K
TEMPERATURE RANGE 65-273 K
TEMPERATURE RANGE 273-400 K