scholarly journals Diffraction theory of nanotwin superlattices with low symmetry phase: Application to rhombohedral nanotwins and monoclinicMAandMBphases

2007 ◽  
Vol 76 (2) ◽  
Author(s):  
Yu U. Wang
Keyword(s):  
Diffraction Theory ◽  
Symmetry Phase ◽  
Low Symmetry

Topotactic Growth of Free-Standing Two-Dimensional Perovskite Niobates with Low Symmetry Phase

Nano Letters ◽  
2021 ◽  
Author(s):  
Fei Zhou ◽  
Yang Li ◽  
Xingqi Liao ◽  
Shuren Lin ◽  
Haizeng Song ◽  
...  
Keyword(s):  
Two Dimensional ◽  
Free Standing ◽  
Symmetry Phase ◽  
Low Symmetry

Algorithms for determining the phase of RHEED oscillations

2015 ◽  
Vol 48 (6) ◽  
pp. 1927-1934 ◽  
Author(s):  
Zbigniew Mitura ◽  
Sergei L. Dudarev
Keyword(s):  
Experimental Data ◽  
Direct Method ◽  
Incident Beam ◽  
Diffraction Theory ◽  
High Energy ◽  
Angle Of Incidence ◽  
High Energy Electron ◽  
Dynamical Diffraction ◽  
Glancing Angle ◽  
Low Symmetry

Oscillations of reflection high-energy electron diffraction (RHEED) intensities are computed using dynamical diffraction theory. The phase of the oscillations is determined using two different approaches. In the first, direct, approach, the phase is determined by identifying the time needed to reach the second oscillation minimum. In the second approach, the phase is found using harmonic analysis. The two approaches are tested by applying them to oscillations simulated using dynamical diffraction theory. The phase of RHEED oscillations observed experimentally is also analysed. Experimental data on the variation of the phase as a function of the glancing angle of incidence, derived using the direct method, are compared with the values computed using both the direct and harmonic methods. For incident-beam azimuths corresponding to low-symmetry directions, both approaches produce similar results.

scholarly journals Temperature controlled c axis elongated low symmetry phase BiFeO3 thin film on STO substrate

AIP Advances ◽  
2013 ◽  
Vol 3 (1) ◽  
pp. 012110 ◽  
Author(s):  
Peng Ren ◽  
Soon Khuen Cho ◽  
Peng Liu ◽  
Lu You ◽  
Xi Zou ◽  
...  
Keyword(s):  
Thin Film ◽  
Bifeo3 Thin Film ◽  
Symmetry Phase ◽  
Temperature Controlled ◽  
Low Symmetry

scholarly journals Group-theoretical analysis of 1:3 A-site-ordered perovskite formation

2019 ◽  
Vol 75 (2) ◽  
pp. 379-397 ◽  
Author(s):  
Mikhail V. Talanov
Keyword(s):  
Phase Transitions ◽  
Theoretical Analysis ◽  
Perovskite Structure ◽  
Functional Materials ◽  
Order Parameters ◽  
Space Group ◽  
Symmetry Phase ◽  
Structural Mechanisms ◽  
Low Symmetry ◽  
Group Theoretical Analysis

The quadruple perovskites AA′3 B 4 X 12 are characterized by an extremely wide variety of intriguing physical properties, which makes them attractive candidates for various applications. Using group-theoretical analysis, possible 1:3 A-site-ordered low-symmetry phases have been found. They can be formed from a parent Pm{\bar 3}m perovskite structure (archetype) as a result of real or hypothetical (virtual) phase transitions due to different structural mechanisms (orderings and displacements of atoms, tilts of octahedra). For each type of low-symmetry phase, the full set of order parameters (proper and improper order parameters), the calculated structure, including the space group, the primitive cell multiplication, splitting of the Wyckoff positions and the structural formula were determined. All ordered phases were classified according to the irreducible representations of the space group of the parent phase (archetype) and systematized according to the types of structural mechanisms responsible for their formation. Special attention is paid to the structural mechanisms of formation of the low-symmetry phase of the compounds known from experimental data, such as: CaCu3Ti4O12, CaCu3Ga2Sn2O12, CaMn3Mn4O12, Ce1/2Cu3Ti4O12, LaMn3Mn4O12, BiMn3Mn4O12 and others. For the first time, the phenomenon of variability in the choice of the proper order parameters, which allows one to obtain the same structure by different group-theoretical paths, is established. This phenomenon emphasizes the fundamental importance of considering the full set of order parameters in describing phase transitions. Possible transition paths from the archetype with space group Pm{\bar 3}m to all 1:3 A-site-ordered perovskites are illustrated using the Bärnighausen tree formalism. These results may be used to identify new phases and interpret experimental results, determine the structural mechanisms responsible for the formation of low-symmetry phases as well as to understand the structural genesis of the perovskite-like phases. The obtained non-model group-theoretical results in combination with crystal chemical data and first-principles calculations may be a starting point for the design of new functional materials with a perovskite structure.

scholarly journals Low symmetry phase in (001) BiFeO3 epitaxial constrained thin films

2005 ◽  
Vol 86 (18) ◽  
pp. 182905 ◽  
Author(s):  
Guangyong Xu ◽  
H. Hiraka ◽  
G. Shirane ◽  
Jiefang Li ◽  
Junling Wang ◽  
...  
Keyword(s):  
Thin Films ◽  
Symmetry Phase ◽  
Low Symmetry

Evidence for precursor clusters associated with structural phase transitions in antifluorite crystals

1982 ◽  
Vol 60 (4) ◽  
pp. 397-398 ◽  
Author(s):  
Robin L. Armstrong ◽  
Marie D'Iorio ◽  
Maximo E. Ramia
Keyword(s):  
Phase Transitions ◽  
Temperature Dependence ◽  
Structural Phase ◽  
Indirect Evidence ◽  
Cubic Phase ◽  
Structural Phase Transitions ◽  
Type Phase ◽  
Symmetry Phase ◽  
Nuclear Quadrupole ◽  
Low Symmetry

Measurements of the temperature dependence of the intensities of the halogen nuclear quadrupole resonances in K2PtBr6 and K2ReCl6, in the cubic phase are reported. These results provide indirect evidence for the formation of dynamic clusters of the low symmetry phase as a precursor to the occurrence of rotative type phase transitions to tetragonal structures in these crystals.

Enhanced piezoelectric properties in Li Bi1-Nb Fe1-O3 films contributed by low-symmetry phase and self-polarization

2019 ◽  
Vol 45 (3) ◽  
pp. 3723-3728 ◽  
Author(s):  
Yafei Hou ◽  
Renlu Han ◽  
Yang Liu ◽  
Laihui Luo ◽  
Weiping Li ◽  
...  
Keyword(s):  
Piezoelectric Properties ◽  
Symmetry Phase ◽  
Low Symmetry
Sign in / Sign up

Export Citation Format

Share Document