Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference (한국전기전자재료학회:학술대회논문집)

The Korean Institute of Electrical and Electronic Material Engineers (한국전기전자재료학회)
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Ion Transport and High Frequency Dielectric of the Hollandite Nax$(Ti_{8-x}Cr_x)O_{16}$

Hollandite Nax$(Ti_{8-x}Cr_x)O_{16}$의 이온 전송과 고유전율 특성

  • Yun, Ju-Ho (Department of Electrical Engineering, Dongshin University) ;
  • Li, Ying (Department of Electrical Engineering, Dongshin University) ;
  • Choi, Yong-Sung (Department of Electrical Engineering, Dongshin University) ;
  • Lee, Kyung-Sup (Department of Electrical Engineering, Dongshin University)
  • 윤주호 (동신대학교 전기공학과) ;
  • 이영 (동신대학교 전기공학과) ;
  • 최용성 (동신대학교 전기공학과) ;
  • 이경섭 (동신대학교 전기공학과)
  • Published : 2008.11.06
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Abstract

The Velocity Autocorrelation Function (VAF) of the sodium ions is calculated for a range of temperature from 250K to 1000K and converted into the linear ac-conductivity and ac-susceptibility response via Fourier transformation. A peak is found in the conductivity around $6\times10^{12}$ Hz that has some of the character of a Poley absorption. Here it is shown to be due to an harmonically coupled site vibrations of the sodium atoms, which extend only over a limited range. At frequencies below the peak the conductivity tends towards a constant i.e. dc value corresponding to a constant flow of ions through the simulation cell. At high temperatures the conductivity due to this ion transport process behaves like a metal with an insulator to metal transition occurring around a specific temperature.

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