Naslov
Axial oxygen-centered lattice fluctuations associated with the superconducting transition in YBa_2Cu_3O_7

Autori
Conradson, S.D. ; Mustre de Leon, J. ; Batistić, I. ; Bishop, A.R. ; Raistrick, I.D.

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
Bulletin of Americal Physical Society / - : American Physical Society, 1991, 989-989

Skup
APS March meeting

Mjesto i datum
Cincinnati (OH), Sjedinjene Američke Države, 18.03.1991. - 22.03.1991

Vrsta sudjelovanja
Predavanje

Vrsta recenzije
Nije recenziran

Ključne riječi
Axial oxygen, superconductivity

Sažetak
The axial oxygen contributions to the Cu K-edge polarized EXAFS of YBa_2Cu_3O_7 are analyzed from 10<T <105K, using a novel approach in which the radial distribution function is directly calculated from model potentials. The best fit is obtained with a double well potential with two nearly equally, populated axial oxygen sites 0.13A apart. The site separation decreases 0.02A in a region near T_c. This perturbation of the structure is accompanied by a large increase of the tunneling frequency of ~ 80K between the two wells. This change is interpreted in terms of coupling between fluctuations of the superconducting order parameter (in a Ginzburg-Landau formalism) and non-linear phonons derived from the double well potential. Fits to the same axial oxygen contributions to the polarized EXAFS of YBa_2Cu_3O_6.5 and YBa_2Cu_3O_{;7+delta}; at T = 10K, indicate a correlation between the tunneling frequency and T_c.

Izvorni jezik
Engleski

Znanstvena područja
Fizika

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