Effects of Applied Electric Fields on Paramagnetic Resonance in Chrome Alums

This study aims to analyse physical and chemical changes in hard coal samples under the influence of low-intensity electric fields in comparison to the fragments of ejected coal, as well as the coal samples selected from the zones of high and low outburst hazard. We used physical methods including X-raying, electron paramagnetic resonance, thermogravimetric analysis, differential scanning calorimetry, laser diffraction analysis of particle sizes, IR-spectrometry, nuclear magnetic resonance, and Raman spectroscopy. It has been shown that destruction of coal organic matter (COM) can be caused not only by mechanical impacts or thermal influences but also weak electric fields. Scientific novelty consists in the fact that for the first time we established the identity of the COM destruction mechanism of mechanical-chemical activation and weak electric fields influencing on the previously destabilized coal microstructure. The destruction mechanism is based on thermal field regularities in both cases. The results obtained are of practical significance for the technologies of coal conversion to other products. The research results can be useful in the development of methods for reducing outburst hazard in coal mines.

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Ferroelectric and Magnetic Characterization of Ferroic Pb(Fe0.5Nb0.5)O3 Ceramics

MRS Proceedings ◽

10.1557/proc-0966-t03-05 ◽

2006 ◽

Vol 966 ◽

Cited By ~ 1

Author(s):

Oscar Raymond ◽

Reynaldo Font ◽

Guillermo Alvarez ◽

Jorge Portelles ◽

Gopalan Srinivasan ◽

...

Keyword(s):

Electric Fields ◽

Remanent Polarization ◽

Antiferromagnetic Order ◽

Paramagnetic Resonance ◽

Dielectric Characterization ◽

Morphological Studies ◽

Impedance Spectroscopy Technique ◽

Points Of View ◽

Electron Paramagnetic

ABSTRACTSingle phase multifunctional materials such as Pb(Fe0.5 Nb0.5)O3 (PFN), where ferroelectric and magnetic order coexist, are very promising and have great interest from the academic and technological points of view. PFN ceramics have been prepared from different kinds of FeNbO4 precursors with either monoclinic or orthorhombic structures. Crystallographic, compositional and surface morphological studies and the temperature-frequency response carried out and reported in previous works are summarized. Ferroelectric hysteretic, magnetic and magnetoelectric behaviors were measured. The remanent polarization (Pr) and coercive field (EC) as functions of temperature and external electric fields (Eext) were determined. Measurements of magnetic susceptibility (χm) exhibited antiferromagnetic order and, above the Núel point near 122 °K, Curie–Weis behavior; whereas a weak ferromagnetic observed from electron paramagnetic resonance (EPR) is discussed. However, magnetoelectric effects were not observed. Ferroelectric and magnetic behaviors, as functions of the kind of precursor used in the preparation, are discussed and correlated with the previous dielectric characterization where microstructural and equivalent circuit models were established using the impedance spectroscopy technique.

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Control of Metal Alloy Oxidation with Electric Fields

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100071260 ◽

1973 ◽

Vol 31 ◽

pp. 164-165

Author(s):

R. R. Dils ◽

P. S. Follansbee

Keyword(s):

Electric Fields ◽

Oxidation Process ◽

Base Alloy ◽

Oxide Surface ◽

Platinum Electrodes ◽

Insulating Layer ◽

Iron Base Alloy ◽

Alloy Oxidation ◽

Aluminum Oxide Layer ◽

And Control

Electric fields have been applied across oxides growing on a high temperature alloy and control of the oxidation of the material has been demonstrated. At present, three-fold increases in the oxidation rate have been measured in accelerating fields and the oxidation process has been completely stopped in a retarding field.The experiments have been conducted with an iron-base alloy, Pe 25Cr 5A1 0.1Y, although, in principle, any alloy capable of forming an adherent aluminum oxide layer during oxidation can be used. A specimen is polished and oxidized to produce a thin, uniform insulating layer on one surface. Three platinum electrodes are sputtered on the oxide surface and the specimen is reoxidized.

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Electron-Mirror Microscopic Aspects of Ferroelectric Domains of BaTiO3 And Ca2Sr (C2H5CO2)6

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100069387 ◽

1970 ◽

Vol 28 ◽

pp. 478-479

Author(s):

Teruo Someya ◽

Jinzo Kobayashi

Keyword(s):

Surface Layer ◽

Electric Fields ◽

Quantitative Study ◽

Recent Progress ◽

Ferroelectric Domain ◽

Resolving Power ◽

Surface Pattern ◽

Crystal Surfaces ◽

One Dimensional ◽

Ferroelectric Domains

Recent progress in the electron-mirror microscopy (EMM), e.g., an improvement of its resolving power together with an increase of the magnification makes it useful for investigating the ferroelectric domain physics. English has recently observed the domain texture in the surface layer of BaTiO3. The present authors ) have developed a theory by which one can evaluate small one-dimensional electric fields and/or topographic step heights in the crystal surfaces from their EMM pictures. This theory was applied to a quantitative study of the surface pattern of BaTiO3).

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Electron Microscope Observations of Magnetic and Electric Effects

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100069144 ◽

1970 ◽

Vol 28 ◽

pp. 430-431

Author(s):

John Silcox

Keyword(s):

Electron Microscope ◽

Electric Fields ◽

Magnetic Image ◽

Magnetic Effects ◽

Ferromagnetic Films ◽

Diffraction Contrast ◽

Microscope Images ◽

Electric Effects ◽

Image Detail

Several aspects of magnetic and electric effects in electron microscope images are of interest and will be discussed here. Clearly electrons are deflected by magnetic and electric fields and can give rise to image detail. We will review situations in ferromagnetic films in which magnetic image effects are the predominant ones, others in which the magnetic effects give rise to rather subtle changes in diffraction contrast, cases of contrast at specimen edges due to leakage fields in both ferromagnets and superconductors and some effects due to electric fields in insulators.

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Electron microscopy studies of PZT ferroelectric film capacitor structures

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100131450 ◽

1992 ◽

Vol 50 (2) ◽

pp. 1364-1365

Author(s):

V. Kaushik ◽

P. Maniar ◽

J. Olowolafe ◽

R. Jones ◽

A. Campbell ◽

...

Keyword(s):

Electric Fields ◽

Sol Gel ◽

Ferroelectric Material ◽

Dielectric Constants ◽

Dielectric Films ◽

Lead Zirconium Titanate ◽

Si Substrate ◽

Film Capacitor ◽

Pzt Films ◽

High Dielectric

Lead zirconium titanate films (Pb (Zr,Ti) O3 or PZT) are being considered for potential application as dielectric films in memory technology due to their high dielectric constants. PZT is a ferroelectric material which shows spontaneous polarizability, reversible under applied electric fields. We report herein some results of TEM studies on thin film capacitor structures containing PZT films with platinum-titanium electrodes.The wafers had a stacked structure consisting of PZT/Pt/Ti/SiO2/Si substrate as shown in Figure 1. Platinum acts as electrode material and titanium is used to overcome the problem of platinum adhesion to the oxide layer. The PZT (0/20/80) films were deposited using a sol-gel method and the structure was annealed at 650°C and 800°C for 30 min in an oxygen ambient. XTEM imaging was done at 200KV with the electron beam parallel to <110> zone axis of silicon.Figure 2 shows the PZT and Pt layers only, since the structure had a tendency to peel off at the Ti-Pt interface during TEM sample preparation.

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Current Status of Solid-State X-Ray Systems

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100117789 ◽

1985 ◽

Vol 43 ◽

pp. 158-161

Author(s):

Martin Peckerar ◽

Anastasios Tousimis

Keyword(s):

Solid State ◽

Electric Fields ◽

Spectral Lines ◽

Current Status ◽

Mobile Charge ◽

Electron Hole ◽

X Ray ◽

Sensing Systems ◽

Transmission Electron ◽

Electron Microscopes

Solid state x-ray sensing systems have been used for many years in conjunction with scanning and transmission electron microscopes. Such systems conveniently provide users with elemental area maps and quantitative chemical analyses of samples. Improvements on these tools are currently sought in the following areas: sensitivity at longer and shorter x-ray wavelengths and minimization of noise-broadening of spectral lines. In this paper, we review basic limitations and recent advances in each of these areas. Throughout the review, we emphasize the systems nature of the problem. That is. limitations exist not only in the sensor elements but also in the preamplifier/amplifier chain and in the interfaces between these components.Solid state x-ray sensors usually function by way of incident photons creating electron-hole pairs in semiconductor material. This radiation-produced mobile charge is swept into external circuitry by electric fields in the semiconductor bulk.

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