Dar, M. Abdullah and Batoo, Khalid Mujasam and Verma, Vivek and Siddiqui, W. A. and Kotnala, R. K. (2009) Synthesis and characterization of nano-sized pure and Al-doped lithium ferrite having high value of dielectric constant. Journal of Alloys and Compounds, 493 (1-2). pp. 553-560. ISSN 0925-8388

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Abstract

Fine particles of Al-doped lithium ferrite of general formula Li0.5AlxFe2.5−xO4 (0.0 ≤ x ≤ 0.4, in step of 0.1) were synthesized by the citrate gel auto combustion method and characterized using XRD, dielectric and impedance spectroscopy. X-ray diffraction studies confirmed that all the samples exhibit single-phase cubic spinel structure. The average particle size of as obtained samples has been found in the range of 38–41 nm. Dielectric permittivity, ac conductivity and complex impedance of all the samples were evaluated as a function of frequency and composition at room temperature. The variation of dielectric properties ɛ′, ɛ″, tan δ and ac conductivity (σac), with frequency reveals that the dispersion is due to Maxwell–Wagner type of interfacial polarization in general and the hopping of charge between Fe+2 and Fe+3. Interestingly, Al-doped nano-crystalline lithium ferrite samples exhibit a very large value for dielectric constant of the order of 105. The impedance spectroscopy technique has been used to study the effect of grain and grain boundary on the electrical properties of Li0.5AlxFe2.5−xO4 ferrites. The analysis of data shows two semicircles corresponding to the grain and grain boundary volume suggesting that grain boundary is mainly involved in conduction mechanism. Magnetic properties have been measured by vibrating sample magnetometer (VSM) for all samples at room temperature.

Item Type:	Article
Additional Information:	Copyright for this article belongs to M/s Elsevier B.V.
Uncontrolled Keywords:	Ferrites; Dielectric behaviour; Ac Conductivity; Impedance spectroscopy
Subjects:	Chemistry Materials Science Metallurgy & Metallurgical Engineering
Divisions:	UNSPECIFIED
Depositing User:	Ms Neetu Chandra
Date Deposited:	16 Jul 2012 12:20
Last Modified:	16 Jul 2012 12:20
URI:	http://npl.csircentral.net/id/eprint/347

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