scholarly journals Electric-field-driven octahedral rotation in perovskite

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Wonshik Kyung ◽  
Choong H. Kim ◽  
Yeong Kwan Kim ◽  
Beomyoung Kim ◽  
Chul Kim ◽  
...  
Keyword(s):  
Surface Layer ◽  
Electric Field ◽  
Physical Properties ◽  
Condensed Matter ◽  
Perovskite Oxides ◽  
Perovskite Materials ◽  
In Situ Control ◽  
Surface Electric Field ◽  
Bulk Structure

AbstractRotation of MO6 (M = transition metal) octahedra is a key determinant of the physical properties of perovskite materials. Therefore, tuning physical properties, one of the most important goals in condensed matter research, may be accomplished by controlling octahedral rotation (OR). In this study, it is demonstrated that OR can be driven by an electric field in Sr2RuO4. Rotated octahedra in the surface layer of Sr2RuO4 are restored to the unrotated bulk structure upon dosing the surface with K. Theoretical investigation shows that OR in Sr2RuO4 originates from the surface electric field, which can be tuned via the screening effect of the overlaid K layer. This work establishes not only that variation in the OR angle can be induced by an electric field, but also provides a way to control OR, which is an important step toward in situ control of the physical properties of perovskite oxides.

scholarly journals Probing the Giant Piezoelectric response of ferroelectric perovskites

2014 ◽  
Vol 70 (a1) ◽  
pp. C150-C150
Author(s):  
Jerome Rouquette ◽  
Manuel Hinterstein ◽  
Julien Haines ◽  
Michael Knapp ◽  
Julia Glaum ◽  
...  
Keyword(s):  
Electric Field ◽  
Ferroelectric Properties ◽  
Structural Phase ◽  
Mechanical Strain ◽  
Domain Wall Motion ◽  
Ferroelectric Materials ◽  
Atomic Scale ◽  
Piezoelectric Response ◽  
Perovskite Materials

By analogy with ferromagnetism and the hysteresis of the magnetic moment with a magnetic field, materials that exhibit a macroscopic spontaneous polarization Ps, which can be reversed under electric field E were defined as ferroelectrics. Ps, the directional order parameter can give rise to different polar structural phase transitions and finally disappear as a function of temperature T and/or hydrostatic pressure P in a transformation from a non-centrosymmetric to a centrosymmetric space group. The physical properties of ferroelectric materials are the basis of many technological applications based on their hysteretic properties (Ps / E in ferroelectric random access memories) or based on their coupled properties (η (mechanical strain)/ E in piezoelectric applications). In order to understand the origin and the mechanisms associated with the ferroelectric properties, "in-situ" structural studies as a function of E, T and P have to be performed. In addition ferroelectric materials exhibit based on their directional properties (Ps) a particular domain configuration which makes the structural understanding of these compounds much more complex. Different scales should be taken into account: from the atomic scale (individual polar displacements) to the macroscopic scale (macroscopic piezoelectric effect) and finally the mesoscopic scale in between, which is governed by the domain wall motion. High piezoelectric/ferroelectric properties in lead perovskite materials (PZT, PMN, PZN) are structurally linked to strong disorder which can be characterized by the presence of diffuse scattering in diffraction experiments and by nanosized domains. Here we will present "in-situ" characterization in lead perovskite materials as a function of the applied electric field based on X-ray and neutron diffraction and EXAFS techniques. A brief overview of the challenges to solve in future studies as a function of pressure and temperature will also be discussed.

Profile Imaging of Silicon Surface Reconstructions

1985 ◽  
Vol 43 ◽  
pp. 262-263
Author(s):  
O.L. Krivanek ◽  
G.J. Wood
Keyword(s):  
Electron Microscopy ◽  
Surface Structure ◽  
Structure Determination ◽  
Silicon Surface ◽  
Good Resolution ◽  
Surface Reconstructions ◽  
Bulk Structure ◽  
Point To Point ◽  
The Relationship

Electron microscopy at 0.2nm point-to-point resolution, 10-10 torr specimei region vacuum and facilities for in-situ specimen cleaning presents intere; ing possibilities for surface structure determination. Three methods for examining the surfaces are available: reflection (REM), transmission (TEM) and profile imaging. Profile imaging is particularly useful because it giv good resolution perpendicular as well as parallel to the surface, and can therefore be used to determine the relationship between the surface and the bulk structure.

The Effect of Roughness Features on Mos Surface Electric Field and Fowler-Nordheim Tunneling Behavior

1997 ◽  
Vol 473 ◽  
Author(s):  
Heng-Chih Lin ◽  
Edwin C. Kan ◽  
Toshiaki Yamanaka ◽  
Simon J. Fang ◽  
Kwame N. Eason ◽  
...  
Keyword(s):  
Electric Field ◽  
Three Dimensional ◽  
Tunneling Current ◽  
Gate Oxide ◽  
Oxide Thickness ◽  
Interface Roughness ◽  
Normal Electric Field ◽  
Surface Electric Field ◽  
Tunneling Behavior ◽  
Nordheim Tunneling

ABSTRACTFor future CMOS GSI technology, Si/SiO2 interface micro-roughness becomes a non-negligible problem. Interface roughness causes fluctuations of the surface normal electric field, which, in turn, change the gate oxide Fowler-Nordheim tunneling behavior. In this research, we used a simple two-spheres model and a three-dimensional Laplace solver to simulate the electric field and the tunneling current in the oxide region. Our results show that both quantities are strong functions of roughness spatial wavelength, associated amplitude, and oxide thickness. We found that RMS roughness itself cannot fully characterize surface roughness and that roughness has a larger effect for thicker oxide in terms of surface electric field and tunneling behavior.

scholarly journals Electrochemical bubble generation via hydrazine oxidation for the in situ control of an electrodeposited conducting polymer micro/-nanostructure

RSC Advances ◽  
2021 ◽  
Vol 11 (18) ◽  
pp. 11020-11025
Author(s):  
David Possetto ◽  
Luciana Fernández ◽  
Gabriela Marzari ◽  
Fernando Fungo
Keyword(s):  
Conducting Polymer ◽  
Electrochemical Method ◽  
Bubble Generation ◽  
Hydrazine Oxidation ◽  
In Situ Control

An electrochemical method to manipulate the size and density of electrodeposited polypyrrole structures at the micro-nanoscale by the discharge of hydrazine.

scholarly journals Microstructural Characteristics of Frazil Particles and the Physical Properties of Frazil Ice in the Yellow River, China

Crystals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 617
Author(s):  
Yaodan Zhang ◽  
Zhijun Li ◽  
Yuanren Xiu ◽  
Chunjiang Li ◽  
Baosen Zhang ◽  
...  
Keyword(s):  
Physical Properties ◽  
Yellow River ◽  
The Yellow River ◽  
Ice Crystal ◽  
Microstructural Characteristics ◽  
Air Bubble ◽  
Frazil Ice ◽  
Sediment Content ◽  
Crystal Diameter

Frazil particles, ice crystals or slushy granules that form in turbulent water, change the freezing properties of ice to create “frazil ice”. To understand the microstructural characteristics of these particles and the physical properties of frazil ice in greater depth, an in situ sampler was designed to collect frazil particles in the Yellow River. The ice crystal microstructural characteristics of the frazil particles (morphology, size, air bubble, and sediment) were observed under a microscope, and their nucleation mechanism was analyzed according to its microstructure. The physical properties of frazil ice (ice crystal microstructure, air bubble, ice density, and sediment content) were also observed. The results showed that these microstructures of frazil particles can be divided into four types: granular, dendritic, needle-like, and serrated. The size of the measured frazil particles ranged from 0.1 to 25 mm. Compared with columnar ice, the crystal microstructure of frazil ice is irregular, with a mean crystal diameter less than 5 mm extending in all directions. The crystal grain size and ice density of frazil ice are smaller than columnar ice, but the bubble and sediment content are larger.

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