Effects of average and local structure on the dielectric behavior of (1−x)BaTiO[sub 3]–xLaYO[sub 3] (0≤x≤0.40) ceramics

FETEIRA, Antonio, SINCLAIR, D. C. and LANAGAN, M. T. (2010). Effects of average and local structure on the dielectric behavior of (1−x)BaTiO[sub 3]–xLaYO[sub 3] (0≤x≤0.40) ceramics. Journal of Applied Physics, 108 (1), 014112.

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Official URL: http://dx.doi.org/10.1063/1.3459897
Link to published version:: 10.1063/1.3459897

Abstract

The dielectric properties of dense ceramics of (1−x)BaTiO3–xLaYO3 (LBTY) (0 ≤ x ≤ 0.40) were characterized in the temperature range 10 to 450 K. The Curie temperature, Tc, of LBTY ceramics decreases at a rate of −23 K/at. % (La,Y) for x<0.10 but increases at +7 K/at. % (La,Y) for x ≥ 0.20. The room temperature relative permittivity, εRT, decreases from ∼ 2000 for x = 0.10 to ∼ 57 for x = 0.40. This variation is accompanied by a substantial reduction in the temperature dependence of the relative permittivity, εr, and also by the emergence of relaxor ferroelectric-like behavior at x>0.05. The gradual transition from a classical ferroelectric to a relaxor-type response results from disruption of the long-range ferroelectric order, believed to be caused by a nanoclustering phenomenon. x = 0.10 exhibits all the characteristic features of a relaxor-ferroelectric, i.e., εr decreases and tan δ increases with increasing frequency. For x>0.20 the relaxor behavior becomes progressively more subtle, suggesting a weaker coupling between the polar nanoregions. The poor microwave dielectric properties of LBTY ceramics, in particular for x = 0.40, which exhibit εRT ∼ 57 and a quality factor of ∼ 755 GHz are attributed to phase separation on the nanometer scale.

Item Type: Article
Research Institute, Centre or Group: Materials and Engineering Research Institute > Structural Materials and Integrity Research Centre > Centre for Corrosion Technology
Identification Number: 10.1063/1.3459897
Depositing User: Hilary Ridgway
Date Deposited: 06 Jun 2012 10:59
Last Modified: 06 Jun 2012 10:59
URI: http://shura.shu.ac.uk/id/eprint/5317

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