Naslov
Long-range pairing of bismuth atoms and the modulations in Bi_2Sr_2CaCu_2O_8+x high temperature superconductor

Autori
Kunstelj, Dragan ; Babić, Dinko ; Bagović, D. ; Leontić, Boran ; Vučić, Zlatko ; Gladić, Jadranko

Izvornik
Physica status solidi. A, Applied research (0031-8965) 165 (1998), 2; 467-482

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
HREM ; modulirane strukture ; stehiometrija kisika
(HREM ; modulated structures ; oxygen stoichiometry)

Sažetak
Modulations and "pairing" of Bi atoms in the Bi_2Sr_2CaCu_2O8+x high-temperature superconductor are simultaneously observed on the high resolution electron micrographs, viewed along the [101] crystal direction. We analyze the obtained images by laser diffraction and photodensitometric technique applied to the negatives. The "pairing" of Bi atoms is assumed to be connected with the regular Bi 6sp lone-pair ordering. The shift of the Bi atoms in the "pairing" is estimated to be 0.3 Angstrom. By the Fourier transform of the optical modulation we estimate the period of the structure modulation in the direction perpendicular to the "pairing" to be 9.76 times the period of the average crystal-plane spacing. The analysis of the structure is supported by computer simulations. We set up a model for the extra oxygen arrangement, on the basis of which we estimate the extra oxygen content to be x ~ 0.33 per molecule.

Izvorni jezik
Engleski

Znanstvena područja
Fizika

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