High dielectric non-linear properties of the Pb[(Mg1/3Nb2/3)0.8(Sc1/2Nb1/2)0.2]O3 ceramics

Pure perovskite Pb[(Mg1/3Nb2/3)0.8(Sc1/2Nb1/2)0.2]O3 (PMNSN) ceramics were prepared via a modified ‘columbite-type’ method. The 1:1 B-site ordered structure was detected by X-ray diffraction and transmission electron microscopy. The dielectric relaxation behavior was described by a Lorentz relation and a small polaron over the Curie temperature range. The dielectric tunability properties were investigated at 300 K and 10 kHz. A high dielectric tunability (∼ 75% at 30 kV/cm), low dielectric loss (∼ 0.003) and high figure of merit (∼ 250) of PMNSN, indicate that PMNSN is a promising dielectric tunable material. The high dielectric non-linear behavior of PMNSN was further discussed in terms of the Landau–Ginsberg–Devonshire thermodynamic theory completed with a Langevin term that describes the contribution of the re-orientation of the polar nanoclusters to the non-linear ɛ(E) dependences.

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► A Lorentz relation and a small polaron over the curie temperature range can describe the relaxation behaviors of the Pb[(Mg1/3Nb2/3)0.8(Sc1/2Nb1/2)0.2]O3 ceramics possessing 1:1 B-site partially ordered perovskite structure.
► High dielectric tunability, low dielectric loss and high figure of merit make the Pb[(Mg1/3Nb2/3)0.8(Sc1/2Nb1/2)0.2]O3 ceramics an attractive material for tunable device applications.
► The high dielectric non-linear behavior is related not only to the contribution of the ‘intrinsic’ lattice phonon polarization but also to the contribution of the re-orientation of the polar nanoclusters.