Impedance spectroscopy of SrBi{sub 2}Ta{sub 2}O{sub 9} and SrBi{sub 2}Nb{sub 2}O{sub 9} ceramics correlation with fatigue behavior

Journal Article · Wed Oct 01 04:00:00 EDT 1997 · Journal of Materials Research

DOI:https://doi.org/10.1557/JMR.1997.0350· OSTI ID:554346

Chen, T; Thio, C; Desu, S B ^[1]

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1. Materials Science and Engineering Department, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061 (United States)

In this research, a fatigue model for ferroelectric materials is proposed. The reasons for the electrical fatigue resistance of SrBi{sub 2}Ta{sub 2}O{sub 9}(SBT), SrBi{sub 2}Nb{sub 2}O{sub 9}(SBN), and PbZr{sub 1{minus}x}Ti{sub x}O{sub 3}(PZT) are discussed in terms of the bulk ionic conductivities of the compounds. To obtain the bulk ionic conductivity of SBT and SBN, we have used impedance spectroscopy which provides an effective method that allows us to separate the individual contributions of bulk, grain boundaries, and electrode-ferroelectric interfaces from the total capacitor impedance. The bulk ionic conductivities of SBT and SBN ({approximately}10{sup {minus}7}S/cm) are much higher than those of the perovskite ferroelectrics, e.g., PZT ({approximately}10{sup {minus}11}-10{sup {minus}10}S/cm). The high ionic conductivities led us to conclude that the good fatigue resistance of SrBi{sub 2}Ta{sub 2}O{sub 9} and SrBi{sub 2}Nb{sub 2}O{sub 9} is due to easy recovery of defects. Specifically, oxygen vacancies entrapped within the capacitors are easily released, resulting in limited space charge buildup and domain wall pinning during the polarization reversal process. However, the oxygen vacancies in PZT are trapped at trap sites to become space charges, resulting in capacitor fatigue. {copyright} {ital 1997 Materials Research Society.}

• OSTI ID: 554346
• Journal Information: Journal of Materials Research, Journal Name: Journal of Materials Research Journal Issue: 10 Vol. 12; ISSN JMREEE; ISSN 0884-2914
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
BISMUTH OXIDES
CERAMICS
DIELECTRIC PROPERTIES
ELECTRIC IMPEDANCE
FERROELECTRIC MATERIALS
GRAIN BOUNDARIES
IONIC CONDUCTIVITY
NIOBIUM OXIDES
STRONTIUM OXIDES
TANTALUM OXIDES