Electron density distribution in BaPb{sub 1-x}Sb{sub x}O{sub 3} superconducting oxides studied by double nuclear magnetic resonance methods

Journal Article · Tue Nov 15 00:00:00 EST 2011 · Journal of Experimental and Theoretical Physics

DOI:https://doi.org/10.1134/S1063776111130085· OSTI ID:22027981

Ogloblichev, V V; Arapova, I Yu; Sadykov, A V; Gerashchenko, A P; Verkhovskii, S V ^[1]

---

1. Russian Academy of Sciences, Institute of Metal Physics, Ural Branch (Russian Federation)

The effect of charge disorder on the formation of an inhomogeneous state of the electron system in the conduction band in BaPb{sub 1-x}Sb{sub x}O{sub 3} superconducting oxides is investigated experimentally by NMR methods. The NMR spectra of {sup 17}O are measured systematically, and the contributions from {sup 17}O atoms with different cation nearest surroundings are identified. It is found that microscopic regions with an elevated spin density of charge carriers are formed within two coordination spheres near antimony ions. Nuclei of the superconducting phase of the oxide (regions with an elevated antimony concentration) microscopically distributed over the sample are detected in compounds with x = 0.25 and 0.33. Experiments in which a double resonance signal of the spin echo of {sup 17}O-{sup 207}Pb and {sup 17}O-{sup 121}Sb are measured in the metal phase of BaPb{sub 1-x}Sb{sub x}O{sub 3} oxides are carried out for the first time. The constants of indirect heteronuclear spin-spin {sup 17}O-{sup 207}Pb interaction are determined as functions of the local Knight shift {sub 207}Ks. The estimates of the constants of the indirect interaction between the nuclei of the nearest neighbors (O-Pb and Pb-Pb atoms) and analysis of evolution of the NMR spectra of {sup 17}O upon a change in the antimony concentration are convincing evidence in favor of the development of a microscopically inhomogeneous state of the electron system in the metal phase of BaPb{sub 1-x}Sb{sub x}O{sub 3} oxides.

• OSTI ID: 22027981
• Journal Information: Journal of Experimental and Theoretical Physics, Vol. 113, Issue 5; Other Information: Copyright (c) 2011 Pleiades Publishing, Ltd.; Country of input: International Atomic Energy Agency (IAEA); ISSN 1063-7761
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
36 MATERIALS SCIENCE
ANTIMONY
ANTIMONY 121
ANTIMONY COMPOUNDS
ANTIMONY IONS
BARIUM COMPOUNDS
CHARGE CARRIERS
ELECTRON DENSITY
ELECTRONIC STRUCTURE
ELECTRONS
KNIGHT SHIFT
LEAD 207
LEAD OXIDES
NMR SPECTRA
NUCLEAR MAGNETIC RESONANCE
OXYGEN 17
SPIN
SPIN ECHO
SUPERCONDUCTORS