Escape-field distribution for escape from a metastable potential well subject to a steadily increasing bias field

1995 ◽  
Vol 51 (21) ◽  
pp. 15592-15595 ◽  
Author(s):  
Anupam Garg
Keyword(s):  
Field Distribution ◽  
Bias Field ◽  
Potential Well ◽  
Metastable Potential

THE KRAMERS TURNOVER PROBLEM: RECROSSING EFFECTS AND THE ENERGY DIFFUSION DESCRIPTION OF THERMAL ACTIVATION

1989 ◽  
Vol 03 (14) ◽  
pp. 1093-1099 ◽  
Author(s):  
H. DEKKER
Keyword(s):  
Spectral Analysis ◽  
Brownian Motion ◽  
Thermal Activation ◽  
Phase Space Density ◽  
Potential Well ◽  
Motion Model ◽  
Action Variable ◽  
Energy Diffusion ◽  
Metastable Potential ◽  
Brownian Motion Model

Kramers' Brownian motion model for escape from a metastable potential well is reconsidered in terms of the particle's energy and the action variable near the peak of the barrier. The pertinent phase space density ρ(ε, s) is uniquely determined (i) by means of a spectral analysis and (ii) upon specifying the energy distribution of (re-)entering particles. The ensuing decay rate Γ goes to zero in the low as well as in the high friction limit according to Kramers' original formulae. The nature of the intermediate turnover regime is critically discussed — and a comparison with related recent work by Büttiker, Harris and Landauer, Mel'nikov and Meshkov, and Grabert is made — while a problem with the underlying density is pointed out.

Fatigue in PZT Thin Films

2000 ◽  
Vol 655 ◽  
Author(s):  
V. Shur ◽  
E. Nikolaeva ◽  
E. Shishkin ◽  
I. Baturin ◽  
D. Bolten ◽  
...  
Keyword(s):  
Thin Films ◽  
Distribution Function ◽  
Field Distribution ◽  
Fatigue Behavior ◽  
Bias Field ◽  
New Approach ◽  
Pzt Thin Films ◽  
Theoretical Predictions ◽  
Characteristic Evolution ◽  
Internal Bias

AbstractWe have used the new approach to fatigue phenomenon for analysis of the switching current and C-V characteristic evolution during cycling in PZT thin films. It was shown that in accordance with theoretical predictions the rejuvenation stage precedes the fatigue one. We have demonstrated that fatigue behavior corresponds to the spreading of the internal bias field distribution function during ac switching.

Mean escape time of ballistically transporting Brownian particles due to thermal noise

2014 ◽  
Vol 28 (11) ◽  
pp. 1450063
Author(s):  
Zhan Wu Bai ◽  
Ping Wang
Keyword(s):  
Correlation Time ◽  
Thermal Noise ◽  
Time Derivative ◽  
Thermal Time ◽  
Escape Time ◽  
Potential Well ◽  
Brownian Particles ◽  
Metastable Potential ◽  
The Mean

The mean escape time of Brownian particles from a metastable potential well is investigated under the influence of a thermal time derivative Ornstein–Uhlenbeck noise, which can induce ballistic diffusion of force-free Brownian particles. Compared with the usual Ornstein–Uhlenbeck noise, some new characteristics are obtained. The Brownian particles escape fast remarkably for a larger correlation time of the Ornstein–Uhlenbeck noise. The mean escape time increases as the correlation time decreases, which is contrary to the Ornstein–Uhlenbeck noise case. The escape time for derivative Ornstein–Uhlenbeck noise is longer than that of Ornstein–Uhlenbeck noise for small strength of noise and small correlation time of Ornstein–Uhlenbeck noise. These features are explained by the spectrum features of derivative Ornstein–Uhlenbeck noise and the corresponding dynamical effects.

High Resolution Specimen Area Imaged Under Negligible Field Aberrations

1970 ◽  
Vol 28 ◽  
pp. 540-541 ◽  
Author(s):  
T. Yanaka ◽  
K. Shirota
Keyword(s):  
High Resolution ◽  
Field Distribution ◽  
Image Space ◽  
Beam Deflection ◽  
Objective Lens ◽  
Resolution Limit ◽  
Leakage Flux ◽  
Specimen Area ◽  
Points Of View ◽  
Aberration Theory

It is significant to note field aberrations (chromatic field aberration, coma, astigmatism and blurring due to curvature of field, defined by Glaser's aberration theory relative to the Blenden Freien System) of the objective lens in connection with the following three points of view; field aberrations increase as the resolution of the axial point improves by increasing the lens excitation (k2) and decreasing the half width value (d) of the axial lens field distribution; when one or all of the imaging lenses have axial imperfections such as beam deflection in image space by the asymmetrical magnetic leakage flux, the apparent axial point has field aberrations which prevent the theoretical resolution limit from being obtained.

Field Distribution of Strongly Excited Magnetic Lenses

1975 ◽  
Vol 33 ◽  
pp. 140-141
Author(s):  
M. Strojnik
Keyword(s):  
Flux Density ◽  
Field Distribution ◽  
Optical Axis ◽  
Operating Point ◽  
Pole Piece ◽  
Partial Saturation ◽  
Axial Flux ◽  
The Stability

Magnetic lenses operating in partial saturation offer two advantages in HVEM: they exhibit small cs and cc and their power depends little on the excitation IN. Curve H, Fig. 1, shows that the maximal axial flux density Bz max of one of the lenses investigated changes between points (3) and (4) by 5% as the excitation varies by 40%. Consequently, the designer can relax the requirements concerning the stability of the lens current supplies. Saturated lenses, however, can only be used if (i) unwanted fields along the optical axis can be controlled, (ii) 'wobbling' of the optical axis due to inhomogeneous saturation around the pole piece faces is prevented, (iii) ample ampere-turns can be squeezed into the space available, and (iv) the lens operating point covers a sufficient range of accelerating voltages.

Comparison of random field strengths in (1-x)SrTiO3-xBiFeO3 and (1-x)SrTiO3-xBaTiO3 relaxor ferroelectrics by means of acoustic emission

2020 ◽  
Vol 92 (2) ◽  
pp. 20401
Author(s):  
Evgeniy Dul'kin ◽  
Michael Roth
Keyword(s):  
Acoustic Emission ◽  
Random Field ◽  
Electric Fields ◽  
Bias Field ◽  
Relaxor Ferroelectrics ◽  
External Bias ◽  
Field Strengths

In relaxor (1-x)SrTiO3-xBiFeO3 ferroelectrics ceramics (x = 0.2, 0.3 and 0.4) both intermediate temperatures and Burns temperatures were successfully detected and their behavior were investigated in dependence on an external bias field using an acoustic emission. All these temperatures exhibit a non-trivial behavior, i.e. attain the minima at some threshold fields as a bias field enhances. It is established that the threshold fields decrease as x increases in (1-x)SrTiO3-xBiFeO3, as it previously observed in (1-x)SrTiO3-xBaTiO3 (E. Dul'kin, J. Zhai, M. Roth, Phys. Status Solidi B 252, 2079 (2015)). Based on the data of the threshold fields the mechanisms of arising of random electric fields are discussed and their strengths are compared in both these relaxor ferroelectrics.

GIANT RESONANCES IN A POTENTIAL WELL : A SEMICLASSICAL DESCRIPTION

1987 ◽  
Vol 48 (C2) ◽  
pp. C2-19-C2-26
Author(s):  
X. VIÑAS ◽  
A. GUIRAO
Keyword(s):  
Potential Well ◽  
Giant Resonances
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