Effects of average and local structure on the dielectric behavior of (1-x)BaTiO3-xLaYO3 (0≤x≤0.40) ceramics

A. Feteira, D. C. Sinclair, Michael T. Lanagan

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Abstract

The dielectric properties of dense ceramics of (1-x) BaTiO 3-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.

Original languageEnglish (US)
Article number014112
JournalJournal of Applied Physics
Volume108
Issue number1
DOIs
StatePublished - Jul 1 2010

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All Science Journal Classification (ASJC) codes

  • Physics and Astronomy(all)

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