Impedance spectroscopy of epitaxial multiferroic thin films

Schmidt, R. and Eerenstein, W. and Winiecki, T. and Morrison, F. D. and Midgley, P. A. (2007) Impedance spectroscopy of epitaxial multiferroic thin films. Physical Review B, 75 (24). p. 245111. ISSN 1098-0121 DOI

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Temperature dependent impedance spectroscopy enables the many contributions to the dielectric and resistive properties of condensed matter to be deconvoluted and characterized separately. We have achieved this for multiferroic epitaxial thin films of BiFeO3 BFO and BiMnO3 BMO, key examples of materials with strong magnetoelectric coupling. We demonstrate that the true film capacitance of the epitaxial layers is similar to that of the electrode interface, making analysis of capacitance as a function of film thickness necessary to achieve deconvolution. We modeled non-Debye impedance response using Gaussian distributions of relaxation times and reveal that conventional resistivity measurements on multiferroic layers may be dominated by interface effects. Thermally activated charge transport models yielded activation energies of 0.60±0.05 eV BFO and 0.25±0.03 eV BMO, which is consistent with conduction dominated by oxygen vacancies BFO and electron hopping BMO. The intrinsic film dielectric constants were determined to be 320±75 BFO and 450±100 BMO.

Item Type: Article
Uncontrolled Keywords: IA55 2007 P
Subjects: 03 - Mineral Sciences
Divisions: 03 - Mineral Sciences
04 - Palaeobiology
Journal or Publication Title: Physical Review B
Volume: 75
Page Range: p. 245111
Identification Number:
Depositing User: Sarah Humbert
Date Deposited: 16 Feb 2009 13:03
Last Modified: 23 Jul 2013 10:08

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