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Nanocrystalline and bulk Li2TiO3 having monoclinic structure were prepared by mechanical alloying as well as conventional ceramic route. Complex impedance analysis in the frequency range of 100 Hz–1 MHz over a wide range of temperature (50–500 ℃) indicates the presence of grain boundary effect along with the bulk contribution. The frequency-dependent conductivity plots exhibit power law dependence, suggesting three types of conduction in the material: low-frequency (100 Hz–1 kHz) conductivity showing long-range translational motion of electrons (frequency independent), mid-frequency (1–10 kHz) conductivity showing short-range hopping of charge carriers and high-frequency (10 kHz–1 MHz) conductivity showing conduction due to localized orientation of hopping mechanism. The electrical conductivity measurement of nanocrystalline and bulk Li2TiO3 with temperature shows the negative temperature coefficient of resistance (NTCR) behavior. The activation energy (0.77 eV for nano sample and 0.88 eV for bulk sample) study shows the conduction mechanism in both samples. The low activation energies of the samples suggest the presence of singly ionized oxygen vacancies in the conduction process.


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Electrical properties of bulk and nano Li2TiO3 ceramics:A comparative study

Show Author's information Umasankar DASHa( )Subhanarayan SAHOObParitosh CHAUDHURIcS. K. S. PARASHARaKajal PARASHARa
School of Applied Sciences, KIIT University, Bhubaneswar-751 024, India
Department of Electrical and Electronics Engineering, Trident Academy of Technology, Bhubaneswar-751 024, India
Institute for Plasma Research, Bhat, Gandhinagar-382 428, India

Abstract

Nanocrystalline and bulk Li2TiO3 having monoclinic structure were prepared by mechanical alloying as well as conventional ceramic route. Complex impedance analysis in the frequency range of 100 Hz–1 MHz over a wide range of temperature (50–500 ℃) indicates the presence of grain boundary effect along with the bulk contribution. The frequency-dependent conductivity plots exhibit power law dependence, suggesting three types of conduction in the material: low-frequency (100 Hz–1 kHz) conductivity showing long-range translational motion of electrons (frequency independent), mid-frequency (1–10 kHz) conductivity showing short-range hopping of charge carriers and high-frequency (10 kHz–1 MHz) conductivity showing conduction due to localized orientation of hopping mechanism. The electrical conductivity measurement of nanocrystalline and bulk Li2TiO3 with temperature shows the negative temperature coefficient of resistance (NTCR) behavior. The activation energy (0.77 eV for nano sample and 0.88 eV for bulk sample) study shows the conduction mechanism in both samples. The low activation energies of the samples suggest the presence of singly ionized oxygen vacancies in the conduction process.

Keywords:

nanocrystalline, complex impedance spectroscopy (CIS), AC conductivity, X-ray diffraction (XRD)
Received: 08 September 2013 Revised: 09 January 2014 Accepted: 10 January 2014 Published: 01 June 2014 Issue date: June 2014
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Publication history

Received: 08 September 2013
Revised: 09 January 2014
Accepted: 10 January 2014
Published: 01 June 2014
Issue date: June 2014

Copyright

© The author(s) 2014

Acknowledgements

We thank the Board of Research in Fusion Science and Technology (BRFST), Institute for Plasma Research Gandhinagar India for support of the research (Grant No. NFP/MAT/F10-01).

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