The origin of the modulated structure in Sr 2 CuO 3+ δ ( δ  = 0.4): [CuO 2 ] in‐plane oxygen vacancy or apical oxygen vacancy?

2019 ◽  
Vol 102 (11) ◽  
pp. 6469-6474
Author(s):  
Xi Shen ◽  
Li‐Peng Cao ◽  
Jian‐Fa Zhao ◽  
Wei‐Peng Wang ◽  
Qing‐Qing Liu ◽  
...  
Keyword(s):  
Oxygen Vacancy ◽  
Apical Oxygen ◽  
Modulated Structure

A TEM study of the incommensurate modulated structure in Sr2CuO3+δ

1995 ◽  
Vol 53 ◽  
pp. 368-369
Author(s):  
Y.Y. Wang ◽  
H. Zhang ◽  
V.P. Dravid ◽  
L.D. Marks ◽  
P.D. Han ◽  
...  
Keyword(s):  
Annealing Treatment ◽  
High Resolution Electron Microscopy ◽  
Apical Oxygen ◽  
Modulated Structure ◽  
Lattice Constants ◽  
Post Annealing ◽  
Transmission Electron ◽  
Resolution Electron ◽  
Occurrence Of Superconductivity ◽  
Electron Energy Loss

Hiroi et al. have recently reported the occurrence of superconductivity at a transition temperature of ~ 70 K in Sr2CuO3+δ. They observed a superstructure with lattice constants of Neutron diffraction studies on this compound by Shimakawa et al. indicate that the apical oxygen is fully occupied, whereas the oxygen in CuO2 plane is half occupied. If oxygen does not fully occupy in the conducting CuO2 planes, it raises doubts about our current understanding of superconductivity in the cuprates, which relies on full oxygen occupancy for the CuO2 planes.Recently, Han et al. observed a dependence of Tc on post annealing treatment of the high pressure synthesized Sr2CuO3+δ. They noticed that heating the sample to 300°C increased the Tc from 70 K to 94 K and that further heating to 450°C caused the sample to lose superconductivity.In order to investigate the structural and microchemical details of Sr2CuO3+δ, transmission electron diffraction, high resolution electron microscopy, and electron energy loss spectroscopy are employed.

Intergrowth of modulated structures in high Tc Bi-Sr-Ca-Cu-O superconductors

1990 ◽  
Vol 48 (4) ◽  
pp. 76-77
Author(s):  
A.Q. He ◽  
G.W. Qiao ◽  
J. Zhu ◽  
H.Q. Ye
Keyword(s):  
Twin Structure ◽  
Modulated Structure ◽  
High Tc ◽  
One Dimensional ◽  
Lattice Constants ◽  
Superconducting Phases ◽  
Modulated Structures ◽  
Layer Structures

Since the first discovery of high Tc Bi-Sr-Ca-Cu-O superconductor by Maeda et al, many EM works have been done on it. The results show that the superconducting phases have a type of ordered layer structures similar to that in Y-Ba-Cu-O system formulated in Bi2Sr2Can−1CunO2n+4 (n=1,2,3) (simply called 22(n-1) phase) with lattice constants of a=0.358, b=0.382nm but the length of c being different according to the different value of n in the formulate. Unlike the twin structure observed in the Y-Ba-Cu-O system, there is an incommensurate modulated structure in the superconducting phases of Bi system superconductors. Modulated wavelengths of both 1.3 and 2.7 nm have been observed in the 2212 phase. This communication mainly presents the intergrowth of these two kinds of one-dimensional modulated structures in 2212 phase.

Characterization of Modulated Structure Through Structure Images and their Computer Simulation

1990 ◽  
Vol 48 (1) ◽  
pp. 70-71
Author(s):  
Kiyomichi Nakai ◽  
Yusuke Isobe ◽  
Chiken Kinoshita ◽  
Kazutoshi Shinohara
Keyword(s):  
Computer Simulation ◽  
High Resolution ◽  
Spherical Aberration ◽  
High Resolution Electron Microscopy ◽  
Basic Mechanism ◽  
Objective Lens ◽  
Specimen Thickness ◽  
Transmitted Beam ◽  
Modulated Structure ◽  
Resolution Electron

Induced spinodal decomposition under electron irradiation in a Ni-Au alloy has been investigated with respect to its basic mechanism and confirmed to be caused by the relaxation of coherent strain associated with modulated structure. Modulation of white-dots on structure images of modulated structure due to high-resolution electron microscopy is reduced with irradiation. In this paper the atom arrangement of the modulated structure is confirmed with computer simulation on the structure images, and the relaxation of the coherent strain is concluded to be due to the reduction of phase-modulation.Structure images of three-dimensional modulated structure along <100> were taken with the JEM-4000EX high-resolution electron microscope at the HVEM Laboratory, Kyushu University. The transmitted beam and four 200 reflections with their satellites from the modulated structure in an fee Ni-30.0at%Au alloy under illumination of 400keV electrons were used for the structure images under a condition of the spherical aberration constant of the objective lens, Cs = 1mm, the divergence of the beam, α = 3 × 10-4 rad, underfocus, Δf ≃ -50nm and specimen thickness, t ≃ 15nm. The CIHRTEM code was used for the simulation of the structure image.

Effect of hot pressing on the modulated structure of Zr0.98Sn0.02TiO4

1998 ◽  
Vol 77 (4) ◽  
pp. 1033-1037 ◽  
Author(s):  
Y. Park, S. A. Song H., G. Kim
Keyword(s):  
Hot Pressing ◽  
Modulated Structure

THE MODULATED STRUCTURE OF NEODYMIUM CRYSTAL

1988 ◽  
Vol 49 (C8) ◽  
pp. C8-339-C8-340
Author(s):  
A. Jaroszewicz ◽  
P. Kociski ◽  
G. Tecza ◽  
J. Kociski
Keyword(s):  
Modulated Structure

Impact Of Synthesis Route on the Water Oxidation Kinetics of Hematite Photoanodes

2020 ◽  
Author(s):  
Camilo A. Mesa ◽  
Ludmilla Steier ◽  
Benjamin Moss ◽  
Laia Francàs ◽  
James E. Thorne ◽  
...  
Keyword(s):  
Oxygen Vacancy ◽  
Reaction Kinetics ◽  
Water Oxidation ◽  
Oxidation Kinetics ◽  
Oxidation Reaction ◽  
Charge Accumulation ◽  
Optical Signals ◽  
Current Voltage ◽  
Voltage Performance ◽  
Kinetics Of

<p><i>Operando</i> spectroelectrochemical analysis is used to determine the water oxidation reaction kinetics for hematite photoanodes prepared using four different synthetic procedures. Whilst these photoanodes exhibit very different current / voltage performance, their underlying water oxidation kinetics are found to be almost invariant. Lower photoanode performance was found to correlate with the observation of optical signals indicative of charge accumulation in mid-gap oxygen vacancy states, indicating these states do not contribute directly to water oxidation.</p>

Enhanced photocatalytic activity of perovskite NaNbO3 by oxygen vacancy engineering

2019 ◽  
Vol 21 (22) ◽  
pp. 11697-11704 ◽  
Author(s):  
Bian Yang ◽  
Jihong Bian ◽  
Lei Wang ◽  
Jianwei Wang ◽  
Yaping Du ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Oxygen Vacancy

Oxygen vacancy engineering can improve the photocatalytic activity of perovskite NaNbO3.

Evolution of spatial spin-modulated structure with La doping in Bi1-yLayFeO3 multiferroics

2021 ◽  
Vol 517 ◽  
pp. 167341 ◽  
Author(s):  
V.S. Pokatilov ◽  
A.O. Makarova ◽  
A.A. Gippius ◽  
A.V. Tkachev ◽  
S.V. Zhurenko ◽  
...  
Keyword(s):  
Modulated Structure ◽  
La Doping

Improvement of reliability of polymer nanocomposite based transparent memory device by oxygen vacancy rich ZnO nanorods

2016 ◽  
Vol 164 ◽  
pp. 53-58 ◽  
Author(s):  
Snigdha Bhattacharjee ◽  
Pranab Kumar Sarkar ◽  
Nandini Roy ◽  
Asim Roy
Keyword(s):  
Oxygen Vacancy ◽  
Zno Nanorods ◽  
Polymer Nanocomposite ◽  
Memory Device
Sign in / Sign up

Export Citation Format

Share Document