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Molecular dynamics simulation of high frequency (10[superscript 10] to 10[superscript 12] Hz) dielectric absorption in the hollandite Na[subscript x](Ti[subscript 8-x]Cr[subscript x])O[subscript 16]

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conference contribution
posted on 15.09.2008, 15:17 by Kien Ling Khoo, Len A. Dissado, John C. Fothergill, Ian J. Youngs
The charge-compensating sodium ions that reside interstitially in the one-dimensional tunnels of the hollandite Nax(Ti8-xCrx)O16 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. A resonance absorption is found,peaking at frequencies between 4.5x1010 and 8.8x1010 Hz at 297K. 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.

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Citation

Proceedings of the 2004 IEEE International Conference on Solid Dielectrics 2004, ICSD 2004, pp. 550-553.

Published in

Proceedings of the 2004 IEEE International Conference on Solid Dielectrics 2004

Publisher

Institute of Electrical and Electronics Engineers (IEEE)

issn

0780383486

Copyright date

2004

Available date

15/09/2008

Publisher version

http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=1350490

Language

en

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