Ordered arrangement of carbon and copper atoms in (C0.4Cu0.6)Sr2(Y0.86Sr0.14)Cu2O7

doi:10.1016/0921-4534(93)90437-U

Physica C: Superconductivity

Volume 207, Issues 1–2, 1 March 1993, Pages 175-184

https://doi.org/10.1016/0921-4534(93)90437-U Get rights and content

Abstract

An ordered arrangement of carbon and copper atoms in the new compound (C_0.4Cu_0.6)Sr₂(Y_0.86Sr_0.14)Cu₂O₇ was investigated by means of electron diffraction and high-resolution electron microscopy. Electron diffraction patters show diffuse superlattice reflections corresponding to a compositional modulation with periods in the range from 2a to 3a along the a-axis and 2c along the c-axis. From observed high-resolution images, it is concluded that the modulated arrangement of carbon and copper atoms is responsible for the diffuse superlattice reflections. It is proposed that this modulated structure consists of two kinds of superstructure units having dimensions of 2a×b×2c and 3a×b×2c. There are two different atomic arrangements in the 3a×b×2c units.

References (7)

Y. Miyazaki et al.
Physica C
(1992)
Y. Miyazaki et al.
Physica C
(1992)
Y. Miyazaki et al.
Physica C
(1992)

There are more references available in the full text version of this article.

Cited by (9)

In situ growth and doping of oxycarbonate Sr<inf>2</inf>CuO<inf>2</inf>(CO<inf>3</inf>) epitaxial thin films
1998, Physica C: Superconductivity and its Applications
Epitaxial cuprate oxycarbonate Sr₂CuO₂(CO₃) thin films have been prepared by metal–organic chemical vapor deposition. The effects of deposition conditions on phase stability have been determined. X-ray diffraction, transmission electron microscopy, Rutherford backscattering spectroscopy, inductively coupled plasma atomic emission spectroscopy, and Fourier transform infrared spectroscopy were used to characterize the oxycarbonate thin films. The resistivity of the undoped Sr₂CuO₂(CO₃) thin films decreases from ∼0.2 Ω cm to ∼0.01 Ω cm upon post annealing in oxygen, but semiconducting behavior is observed. Doping has been achieved through partial substitution of BO₃³⁻ for CO₃²⁻. Superconductivity with a T_{c (onset)} of 34 K and a T_{c (zero)} of 20 K has been obtained.
Carbonate groups and the superconductivity in 123 cuprates Y<inf>0.8</inf>Ca<inf>0.2</inf>Ba<inf>2</inf>Cu<inf>3-x</inf>C<inf>x</inf>O <inf>y</inf>
1996, Physica C: Superconductivity and its Applications
Three ceramic superconductors Y_0.8Ca_0.2Ba₂Cu_3−xC_xO_y (x = 0, 0.13 and 0.34) were prepared both in the oxidized and partially reduced forms. The boundaries of the superconducting regions were estimated to y = 6.40, 6.50 and 6.75 for the three systems, respectively. The role of incorporated CO₃ groups has been investigated by means of electric resistivity, thermoelectric power and AC susceptibility measurements and, for the oxidized samples, by neutron diffraction. The presence of the hole type carriers in the CuO₂ planes was analyzed by the bond strength summation.
Modulated structure in YSr<inf>2</inf>Cu<inf>2.5</inf>B<inf>0.5</inf>O<inf>y</inf> oxide
1994, Physica C: Superconductivity and its applications
The modulated structure in YSr₂Cu_2.5B_0.5O_y is characterized by electron diffraction and high resolution electron microscopy. A structural model is postulated for the modulation, in which the periodic changes are considered due to the ordered arrangement of B and Cu atoms in the 123 structure. Computer calculated images for this model are compared with high resolution electron micrographs. Upon in situ heating, the structural modulation disappears at a temperature of around 760 K. Substitution of Ba for Sr in YSr₂Cu_2.5B_0.5O_y is found to induce superconductivity and affect the structural modulation.
Determination of the superstructure in (Y<inf>0.75</inf>Ce<inf>0.25</inf>)<inf>2</inf>(Sr<inf>0.85</inf>Y<inf>0.15</inf>)<inf>2</inf>AlCu<inf>2</inf>O<inf>9+x</inf> by means of electron microscopy
1993, Physica C: Superconductivity and its applications
Neutron-diffraction experiments have shown that the title compound A1-2212 has an average tetragonal structure closely related to the quasi-tetragonal YBa₂Cu₃O₇ structure, but with the Y layer replaced means of electron diffraction and high-resolution electron microscopy have refined the existing model. A superstructure of corner-linked oxygen tetrahedra coordinating the A1O ions is shown in the AlO layer. The weakness of corrrelations between adjacent AlO layers, and the presence of two orientational variants, may explain why this superstructure was overlooked by neutron-diffraction investigations.
Structural variation in a (Y<inf>1-y</inf>Ca<inf>y</inf>)(Sr<inf>2-x</inf>Ba<inf>x</inf>)(Cu<inf>0.5</inf> B<inf>0.5</inf>)Cu<inf>2</inf>O<inf>7-δ</inf> system
2003, Superconductor Science and Technology
Crystal structures of Copper‐Based High‐T<inf>c</inf> Superconductors
1994, Advanced Materials

View all citing articles on Scopus

View full text