High- Tc/high-coupling relaxed PZT-based single crystal thin films

K. Wasa, T. Matsushima, H. Adachi, T. Matsunaga, Takahiko Yanagitani, T. Yamamoto

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Abstract

Pb(Zr,Ti)O3 (PZT)-based ferroelectric ceramics exhibit high piezoelectricity, however, their Curie temperature (Tc) values are not so high, i.e., Tc < 400 °C. PZT-based piezoelectric thin films with higher Tc would be beneficial for improved micro actuators, sensors, memories, and piezoelectric micro-electro mechanical systems. In-plane biaxial strained PZT thin films in a laminated composite structure are known to exhibit enhanced Tc; however, the thickness of PZT-based thin films is limited to below a critical thickness typically <50 nm. The Tc of relaxed PZT-based thin films with thicknesses greater than the critical thickness is the same as bulk Tc. However, a sort of relaxed PZT-based single-crystal thin films exhibit extraordinary high Tc, Tc = ∼600 °C. In addition, the films show extremely low dielectric constant, ε/εo ∼ 100 with high coupling factor, kt ∼ 0.7, and large remnant polarization, Pr ∼ 100 μC/cm2. These exotic properties would result from the single-domain/single-crystal structure. The enhanced Tc is possibly caused by the highly stable interface between the PZT-based thin films and substrates. Their ferroelectric performances are beyond those of conventional PZT. The high-Tc/high-coupling performances are demonstrated, and the possible mechanisms of the high Tc behavior in relaxed PZT-based single-crystal thin films are discussed.

Original languageEnglish
Article number124106
JournalJournal of Applied Physics
Volume117
Issue number12
DOIs
Publication statusPublished - 2015 Mar 28
Externally publishedYes

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ASJC Scopus subject areas

  • Physics and Astronomy(all)

Cite this

Wasa, K., Matsushima, T., Adachi, H., Matsunaga, T., Yanagitani, T., & Yamamoto, T. (2015). High- Tc/high-coupling relaxed PZT-based single crystal thin films. Journal of Applied Physics, 117(12), [124106]. https://doi.org/10.1063/1.4915947