Atomic-resolution Probing of Anion Migration in Perovskites with In-situ (S)TEM

ABSTRACTPerovskites are promising functional materials for their optoelectronic properties and anion migration plays a key role in their functional performance [1-3]. By using in-situ (S)TEM mechanical and electrical testing in conjunction with 4D-STEM [4,5], we directly observed/probed anion migration in perovskites at atomic resolution (see Figure 1). Here, we studied the mechanism for the anion migration in perovskites such as (PbZr)TiO3 and BaTiO3, which is induced under the mechnaicl/electrical loading. To avoid the influence of the electron beam, we carried out the in-situ (S)TEM study at 60kv with low dose. And to avoid the possible strong size effect and the substrate (interface) influence, we prepared free-standing sub-micrometer single-crystalline structures to perform the experiments. Corresponding EDS and EELS examinations were performed to measure the local chemical change with applied stress and electrical currents. Our observations revealed the coexistence of multiple phase structures and hierarchical domain structures, as well as the greatly enhanced anion drifting and diffusion at the charged domain walls (Figure 2) and phase boundaries. The complex interaction between the local domain evolution and phase transition has been discussed. Based on above investigations, a model for anion migration in perovskire under mechanical/electrical loading has been presented.

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An In-Situ Tem Study of the Dynamic Behavior of Domain Walls in a Free-Standing Lead Titanate Thin Film Under External Stress

MRS Proceedings ◽

10.1557/proc-404-95 ◽

1995 ◽

Vol 404 ◽

Cited By ~ 1

Author(s):

S. B. Ren ◽

C. J. Lu ◽

H. M. Shen ◽

Y. N. Wang

Keyword(s):

Thin Film ◽

Thin Films ◽

Dynamic Behavior ◽

Domain Walls ◽

High Stress ◽

Ferroelectric Thin Film ◽

External Stress ◽

In Situ Tem ◽

Free Standing

AbstractThe evolution of domain structure with external stress in a free-standing PbTiO3 ferroelectric thin film of ˜100nm in thickness is observed by in-situ TEM technique. The thin film is composed of granular grains of ˜100nm in diameter, most of them appear to be single-domained whereas others are multi-domained showing domains of different sizes(5˜20nm). For some single-domained grains new domains appear during tension. For multi-domained grains, rearrangement of domain walls and coarsening of domains have been observed during tension. In many cases the domain walls disappear under high stress, i.e., a multi-domained grain changes into a single-domained grain. However, it is also observed that a large portion of single-domained grains appear not to respond to external stress. The dynamic behavior of domain walls in very thin ferroelectric thin films may help to understand the switching of these very thin films.

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Temperature Dependence of Magnetic Domains and Wall Structures

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010009573x ◽

1972 ◽

Vol 30 ◽

pp. 496-497

Author(s):

Sonoko Tsukahara ◽

Tadami Taoka ◽

Hisao Nishizawa

Keyword(s):

Temperature Dependence ◽

Domain Walls ◽

Magnetic Domain ◽

Iron Film ◽

Objective Lens ◽

Lorentz Microscopy ◽

Domain Structures ◽

Wall Structures ◽

Crystal Films ◽

Metallurgical Structure

The high voltage Lorentz microscopy was successfully used to observe changes with temperature; of domain structures and metallurgical structures in an iron film set on the hot stage combined with a goniometer. The microscope used was the JEM-1000 EM which was operated with the objective lens current cut off to eliminate the magnetic field in the specimen position. Single crystal films with an (001) plane were prepared by the epitaxial growth of evaporated iron on a cleaved (001) plane of a rocksalt substrate. They had a uniform thickness from 1000 to 7000 Å.The figure shows the temperature dependence of magnetic domain structure with its corresponding deflection pattern and metallurgical structure observed in a 4500 Å iron film. In general, with increase of temperature, the straight domain walls decrease in their width (at 400°C), curve in an iregular shape (600°C) and then vanish (790°C). The ripple structures with cross-tie walls are observed below the Curie temperature.

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Innovative Closed-Cell Reactor Permits In Situ Heating and Gas Reactions with Atomic Resolution at Atmospheric Pressure

Microscopy and Microanalysis ◽

10.1017/s1431927612007441 ◽

2012 ◽

Vol 18 (S2) ◽

pp. 1118-1119 ◽

Cited By ~ 2

Author(s):

L. Allard ◽

S.H. Overbury ◽

M.B. Katz ◽

W.C. Bigelow ◽

D. Nackashi ◽

...

Keyword(s):

Atmospheric Pressure ◽

Atomic Resolution ◽

Closed Cell ◽

Cell Reactor ◽

In Situ Heating ◽

Gas Reactions

Extended abstract of a paper presented at Microscopy and Microanalysis 2012 in Phoenix, Arizona, USA, July 29 – August 2, 2012.

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Magnetic Configurations in Modulated Cylindrical Nanowires

Nanomaterials ◽

10.3390/nano11030600 ◽

2021 ◽

Vol 11 (3) ◽

pp. 600

Author(s):

Cristina Bran ◽

Jose Angel Fernandez-Roldan ◽

Rafael P. del Real ◽

Agustina Asenjo ◽

Oksana Chubykalo-Fesenko ◽

...

Keyword(s):

Domain Walls ◽

Magnetocrystalline Anisotropy ◽

Logic Gates ◽

Local Domain ◽

Magnetic Nanowires ◽

Precise Control ◽

Magnetic Layers ◽

State Present ◽

Circular Domains ◽

3D Applications

Cylindrical magnetic nanowires show great potential for 3D applications such as magnetic recording, shift registers, and logic gates, as well as in sensing architectures or biomedicine. Their cylindrical geometry leads to interesting properties of the local domain structure, leading to multifunctional responses to magnetic fields and electric currents, mechanical stresses, or thermal gradients. This review article is summarizing the work carried out in our group on the fabrication and magnetic characterization of cylindrical magnetic nanowires with modulated geometry and anisotropy. The nanowires are prepared by electrochemical methods allowing the fabrication of magnetic nanowires with precise control over geometry, morphology, and composition. Different routes to control the magnetization configuration and its dynamics through the geometry and magnetocrystalline anisotropy are presented. The diameter modulations change the typical single domain state present in cubic nanowires, providing the possibility to confine or pin circular domains or domain walls in each segment. The control and stabilization of domains and domain walls in cylindrical wires have been achieved in multisegmented structures by alternating magnetic segments of different magnetic properties (producing alternative anisotropy) or with non-magnetic layers. The results point out the relevance of the geometry and magnetocrystalline anisotropy to promote the occurrence of stable magnetochiral structures and provide further information for the design of cylindrical nanowires for multiple applications.

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Mobile and immobile boundaries in ferroelectric films

Scientific Reports ◽

10.1038/s41598-021-81516-w ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

P. Yudin ◽

K. Shapovalov ◽

T. Sluka ◽

J. Peräntie ◽

H. Jantunen ◽

...

Keyword(s):

Long Range ◽

Domain Walls ◽

Ferroelectric Properties ◽

Practical Importance ◽

Dynamic Responses ◽

Ferroelectric Films ◽

Domain Structures ◽

Mobile Interfaces ◽

Ferroelastic Domains ◽

Viable Method

AbstractThe intrinsic mobile interfaces in ferroelectrics—the domain walls can drive and enhance diverse ferroelectric properties, essential for modern applications. Control over the motion of domain walls is of high practical importance. Here we analyse theoretically and show experimentally epitaxial ferroelectric films, where mobile domain walls coexist and interact with immobile growth-induced interfaces—columnar boundaries. Whereas these boundaries do not disturb the long-range crystal order, they affect the behaviour of domain walls in a peculiar selective manner. The columnar boundaries substantially modify the behaviour of non-ferroelastic domains walls, but have negligible impact on the ferroelastic ones. The results suggest that introduction of immobile boundaries into ferroelectric films is a viable method to modify domain structures and dynamic responses at nano-scale that may serve to functionalization of a broader range of ferroelectric films where columnar boundaries naturally appear as a result of the 3D growth.

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Preparation of free-standing metal wire arrays by in situ assembly

Journal of Materials Chemistry ◽

10.1039/b804411b ◽

2008 ◽

Vol 18 (33) ◽

pp. 3977 ◽

Cited By ~ 8

Author(s):

Feng Li ◽

John B. Wiley

Keyword(s):

Metal Wire ◽

Free Standing ◽

Wire Arrays

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Atomic-resolution Studies of Ca3Co4O9 using in-situ Scanning Transmission Electron Microscopy

Microscopy and Microanalysis ◽

10.1017/s1431927608083499 ◽

2008 ◽

Vol 14 (S2) ◽

pp. 436-437 ◽

Cited By ~ 1

Author(s):

G Yang ◽

Y Zhao ◽

K Sader ◽

A Bleloch ◽

RF Klie

Keyword(s):

Electron Microscopy ◽

Transmission Electron Microscopy ◽

New Mexico ◽

Scanning Transmission Electron Microscopy ◽

Atomic Resolution ◽

Scanning Transmission Electron ◽

Transmission Electron ◽

Scanning Transmission

Extended abstract of a paper presented at Microscopy and Microanalysis 2008 in Albuquerque, New Mexico, USA, August 3 – August 7, 2008

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Fabrication of cellulosic paper containing zeolitic imidazolate framework and its application in removal of anionic dye from aqueous solution

BioResources ◽

10.15376/biores.16.2.2644-2654 ◽

2021 ◽

Vol 16 (2) ◽

pp. 2644-2654

Author(s):

Zicheng Chen ◽

Huiwen Zhang ◽

Xiangyang He ◽

Guangyuan Fan ◽

Xiaosong Li ◽

...

Keyword(s):

Aqueous Solution ◽

Functional Materials ◽

Anionic Dyes ◽

Zeolitic Imidazolate Framework ◽

Cellulosic Fibers ◽

Simple Filtration ◽

Metal Organic ◽

Potential Strategy ◽

Cellulosic Paper

The combination of metal organic frameworks (MOFs) with other functional materials is a potential strategy for the preparation of advanced MOF-based materials. In this study, a simple approach is reported for the fabrication of cellulosic paper containing zeolitic imidazolate framework (ZIF-8) through in-situ loading in the papermaking process. The results showed that the ZIF-8 was evenly distributed in the paper substrate owing to the multi-layers structure of the cellulosic fibers, although the loading of the ZIF-8 particles on the single cellulosic fiber was nonuniform. The as-prepared ZIF-8 composites can be used as a highly efficient adsorbent material for anionic dyes in aqueous solution thanks to the positive charge on the surface of the ZIF-8 particles. More than 92% of the methyl orange (MO-) dye in the aqueous solution was rapidly removed through a simple filtration process using the ZIF-8 composite cellulosic paper (hand-sheets made in lab) when the content of ZIF-8 in cellulosic paper was high as 25.1%. In addition, the ZIF-8 composite paper had acceptable flexibility and could be reused at least 4 cycles by washing out the adsorbed dye.

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Deepening of domains at e-beam writing on the -Z surface of lithium niobate

Journal of Physics D Applied Physics ◽

10.1088/1361-6463/ac44c1 ◽

2021 ◽

Author(s):

Lyudmila Kokhanchik ◽

Evgenii Emelin ◽

Vadim Vladimirovch Sirotkin ◽

Alexander Svintsov

Keyword(s):

Surface Layer ◽

Electron Beam ◽

Lithium Niobate ◽

Electric Field ◽

Domain Walls ◽

Normal Component ◽

Beam Current ◽

Near Surface ◽

Domain Structures ◽

Sign Inversion

Abstract The focus of the study was to investigate the peculiarities of the domains created by electron beam (e-beam) in a surface layer of congruent lithium niobate, which comparable to a depth of electron beam charge penetration. Direct e-beam writing (DEBW) of different domain structures with a scanning electron microscope was performed on the polar -Z cut. Accelerating voltage 15 kV and e-beam current 100 pA were applied. Different patterns of local irradiated squares were used to create domain structures and single domains. No domain contrast was observed by the PFM technique. Based on chemical etching, it was found that the vertices of the domains created do not reach the surface level. The average deepening of the domain vertices was several hundred nanometers and varied depending on the irradiation dose and the location of the irradiated areas (squares) relative to each other. Computer simulation was applied to analyze the spatial distribution of the electric field in the various irradiated patterns. The deepening was explained by the fact that in the near-surface layer there is a sign inversion of the normal component of the electric field strength vector, which controls the domain formation during DEBW. Thus, with the help of e-beam, domains were created completely located in the bulk, in contrast to the domains that are nucleated on the surface of the -Z cut during the polarization inversion with AFM tip. The detected deepening of e-beam domains suggests the possibility of creating the “head-to-head” domain walls in the near-surface layer lithium niobate by DEBW.

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