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Bismuth Zinc Niobate Pyrochlore, a Relaxor-Like Non-Ferroelectric

Authors

  • Rozana A. M. Osman,

    1. Department of Materials Science and Engineering, University of Sheffield, Sheffield, U.K.
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    • Permanent address: School of Microelectronics Engineering, University Malaysia Perlis, Jejawi, 02600 Arau, Perlis, Malaysia.
  • Nahum Masó,

    1. Department of Materials Science and Engineering, University of Sheffield, Sheffield, U.K.
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  • Anthony R. West

    Corresponding author
    • Department of Materials Science and Engineering, University of Sheffield, Sheffield, U.K.
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Author to whom correspondence should be addressed. e-mail: a.r.west@sheffield.ac.uk

Abstract

Fixed frequency plots of ε′ and tan δ versus temperature for (Bi1.5Zn0.5)(Zn0.5Nb1.5)O7 (BZN) ceramics with the pyrochlore structure show relaxor-like response below ~180 K with frequency-independent permittivity of ~130 above ~180 K and over the frequency range of 103–106 Hz. Impedance data in the range, 10–180 K fit an equivalent circuit derived from the classic dielectric relaxation circuit in which the relaxation resistance is replaced by a constant phase element (CPE). Temperature dependence of the circuit parameters shows that BZN is not ferroelectric; the CPE, which is responsible for the relaxor-like behavior, gradually changes from primarily capacitive to primarily resistive with increasing temperature.

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