Effect of off-center ion substitution in morphotropic lead zirconate titanate
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A detailed study of the effect of off-center donor ion (Sc3+) substitution on structural, microstructural, optical, dielectric, electrical and ferroelectric properties of morphotropic lead zirconate titanate electroceramics with the stoichiometric formula Pb0.85Sc0.10Zr0.53Ti0.47O3 (PSZT), synthesized using a high-energy solid-state reaction technique, was carried out. Powder x-ray diffractometry was used to identify the stabilized tetragonal phase (space group P4mm) with considerably reduced tetragonal strain, c/a = 1.005. An analysis of the thermal dependence of the Raman results indicated a smooth order-disorder displacive (ferroelectric-paraelectric) phase transition as revealed by the observed disappearance of the soft modes A1 (1TO) and A1 (2TO) above 460 K. The dielectric response of Pt/PSZT/Pt metal-ferroelectric-metal (MFM) capacitors was probed over a wide range of thermal excursions (85-600 K) and ac signal frequencies (102-106 Hz). Thermally activated dynamic and static conduction processes indicate hopping conduction mechanism (Eact ≤ 0.015 eV) and the formation of small polarons caused by the electron and/or hole-lattice (phonon) interaction (Eact ≥ 0.1 eV) at low (100−300 K) and high temperatures (300−600 K), respectively. The reduction in remnant polarization obtained is in good agreement with the largely reduced tetragonal strain observed in this sample, ( Pr ∝√(c/a-1) ). DC current conduction is dominated by Poole-Frenkel mechanism that assumes a Coulombic attraction between de-trapped electrons and positively charged stationary defects in the polycrystalline matrix.
Bhattarai , M K , Pavunny , S P , Instan , A A , Scott , J F & Katiyar , R S 2017 , ' Effect of off-center ion substitution in morphotropic lead zirconate titanate ' Journal of Applied Physics , vol 121 , no. 19 , 194102 . DOI: 10.1063/1.4983526
Journal of Applied Physics
© 2017, the Author(s). This work has been made available online in accordance with the publisher’s policies. This is the author created, accepted version manuscript following peer review and may differ slightly from the final published version. The final published version of this work is available at aip.scitation.org / https://doi.org/10.1063/1.4983526
This research was supported by the DOD Grant No. FA9550–16-1–0295. S.P.P. gratefully acknowledges the financial assistance from IFN-NSF under the Grant No. EPS-1002410.
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