Pb(B{sup {prime}}{sub 1/2}B{sup {prime}{prime}}{sub 1/2})O{sub 3}-type perovskites: Part II. Short-range order parameter as a criterion of the distinction between relaxor and normal ferroelectrics

Journal Article · Fri Aug 01 04:00:00 EDT 1997 · Journal of Materials Research

DOI:https://doi.org/10.1557/JMR.1997.0285· OSTI ID:542191

Kim, S; Jang, H M ^[1]

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1. Department of Materials Science and Engineering, and Laboratory for Physics/Chemistry of Dielectric Materials, Pohang University of Science and Technology (POSTECH), Pohang 790-784 (Republic of Korea)

A classification scheme of Pb(B{sup {prime}}{sub 1/2}B{sup {prime}{prime}}{sub 1/2})O{sub 3}-type perovskites with respect to the B-site order parameters was proposed based on the theoretical calculation of the short-range order parameter ({sigma}) using the pair-correlation model. The calculated order parameters predict that a Pb(B{sup {prime}}{sub 1/2}B{sup {prime}{prime}}{sub 1/2})O{sub 3}-type perovskite without any charge difference between B{sup {prime}} and B{sup {prime}{prime}} cations [e.g., Pb(Zr{sub 1/2}Ti{sub 1/2})O{sub 3} (PZT)] is represented by a completely disordered state with the absence of a finite coherence length. On the other hand, a Pb(B{sup {prime}}{sub 1/2}B{sup {prime}{prime}}{sub 1/2})O{sub 3} type perovskite system having different ionic charges is characterized either by the short-range ordering with a nanoscale coherence length or by the macroscopic long-range ordering, depending on the magnitude of ionic charge difference between B{sup {prime}} and B{sup {prime}{prime}} ions. The normal ferroelectricity in Pb(B{sup {prime}}{sub 1/2}B{sup {prime}{prime}}{sub 1/2})O{sub 3}-type complex perovskites was then correlated either with a completely disordered state ({sigma}=0) or with a perfectly ordered state ({sigma}=1), whereas the relaxor behavior was attributed to the nanoscale short-range ordering (0{lt}{sigma}{lt}1) in the configuration of the B-site cations. {copyright} {ital 1997 Materials Research Society.}

• Sponsoring Organization: USDOE
• OSTI ID: 542191
• Journal Information: Journal of Materials Research, Journal Name: Journal of Materials Research Journal Issue: 8 Vol. 12; ISSN JMREEE; ISSN 0884-2914
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CORRELATIONS
DIELECTRIC PROPERTIES
FERROELECTRIC MATERIALS
LEAD OXIDES
ORDER PARAMETERS
ORDER-DISORDER TRANSFORMATIONS
TITANIUM OXIDES
ZIRCONIUM OXIDES