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Author

J. Youngs

Bio: J. Youngs is an academic researcher. The author has contributed to research in topics: Hollandite. The author has an hindex of 1, co-authored 1 publications receiving 1 citations.
Topics: Hollandite

Papers
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Proceedings ArticleDOI
05 Jul 2004
TL;DR: In this paper, a simple model for charge-compensating sodium ions that reside interstitially in the one-dimensional tunnels of the hollandite Na/sub x/(Ti/sub 8-x/Cr/sub X/)O/sub 16/ is used.
Abstract: The charge-compensating sodium ions that reside interstitially in the one-dimensional tunnels of the hollandite Na/sub x/(Ti/sub 8-x/Cr/sub x/)O/sub 16/ are used as a simple model for a fluid. Molecular dynamics are used to calculate the motions of the ions at a range of temperatures between 200 K and 373 K. The polarization response of the system to a step-up electric field is calculated for field strengths between 7.43 MV/m and 74.3 GV/m, and converted to an ac susceptibility. Resonance absorption is found, peaking at frequencies between 4.5/spl times/10/sup 10/ and 8.8/spl times/10/sup 10/ Hz at 297 K. The origin of the response is shown to be the anharmonically coupled ion vibrations damped by ion hopping to neighbouring sites. The relationship of the result to the experimentally observed Poley absorption is explored, and a brief comparison of the calculated dynamics to previous theoretical models is made.

1 citations


Cited by
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Journal ArticleDOI
TL;DR: The barrier crossing time of a particle can be tuned para-metrically by appropriate choice of amplitude and frequency of the oscillating magnetic field by virtue of parametric resonance.
Abstract: We have studied the effect of time dependent magnetic field on the barrier crossing dynamics of a charged particle. An interplay of the magnetic field induced electric field and the applied field reveals several interesting features. For slowly oscillating field the barrier crossing rate increases remarkably particularly at large amplitude of the field. For appreciably large frequency a generically distinct phenomenon appears by virtue of parametric resonance manifested in multiple peaks appearing in the variation of the mean first passage time as a function of the amplitude. The parametric resonance is more robust against the variation of amplitude of the oscillating field compared to the case of variation of frequency. The barrier crossing time of a particle can be tuned para-metrically by appropriate choice of amplitude and frequency of the oscillating magnetic field.

12 citations