Ferroelectric and electrical behavior of (Na{sub 0.5}Bi{sub 0.5})TiO{sub 3} thin films

Journal Article · Mon Aug 02 04:00:00 EDT 2004 · Applied Physics Letters

DOI:https://doi.org/10.1063/1.1771808· OSTI ID:20632703

Zhou, Z H; Xue, J M; Li, W Z; Wang, J; Zhu, H; Miao, J M ^[1]

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1. Department of Materials Science, National University of Singapore, Lower Kent Ridge Road, Singapore 119260 (Singapore)

Sodium bismuth titanate (Na{sub 0.5}Bi{sub 0.5})TiO{sub 3} (NBT) of perovskite structure is among the best known lead-free piezoelectric/ferroelectric that promises a number of applications in sensors and actuators. However, NBT in thin film form has not been properly investigated, although NBT in bulk ceramic form has been widely studied. In this letter, we report the growth of polycrystalline NBT thin films by radio-frequency magnetron sputtering and their ferroelectric behavior. The NBT thin films exhibit a well-defined hysteresis loop, with a remanent polarization of 11.9 {mu}C/cm{sup 2} and coercive field of 37.9 kV/cm when measured at room temperature. There is a steady decrease of dielectric constant in the range of 650-470 over the frequency range of 10-10{sup 5} Hz. A change in the controlling mechanism of electrical behavior from the grain interior to the grain boundary is observed for the NBT thin film with increasing temperature. Hopping of oxygen vacancies trapped at the grain boundaries is responsible for the high dielectric loss at low frequencies and high dc conductivity observed.

• OSTI ID: 20632703
• Journal Information: Applied Physics Letters, Journal Name: Applied Physics Letters Journal Issue: 5 Vol. 85; ISSN APPLAB; ISSN 0003-6951
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
BISMUTH COMPOUNDS
DEPOSITION
DIELECTRIC MATERIALS
GRAIN BOUNDARIES
HYSTERESIS
KHZ RANGE 100-1000
MAGNETRONS
OXYGEN
PERMITTIVITY
PEROVSKITE
PIEZOELECTRICITY
POLARIZATION
POLYCRYSTALS
RADIOWAVE RADIATION
SODIUM COMPOUNDS
SPUTTERING
TEMPERATURE RANGE 0273-0400 K
THIN FILMS
TITANATES
VACANCIES