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Domain Wall Pinning by Grain Boundaries During Electric Field Poling of KNbO3 Thin Films

Published online by Cambridge University Press:  10 February 2011

Venkatraman Gopalan
Affiliation:
CMS MS K765 Los Alamos National Labs, Los Alamos, NM 87545
Rishi Raj
Affiliation:
Dept. of Mechanical Engineering, University of Colorado, Boulder, CO 80309
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Abstract

We present evidence for grain-boundary pinning of domain walls as controlling the electric field poling behavior of KNbO3 thin films. Two epitaxial film systems are compared: (I) film on MgO (100) substrate with KNbO3 (110)// 120Å SrTiO3 (100) //MgO(lOO) and (II) film on SrTiO3 (100) substrate with KNbO3 (110)// SrTiO3 (100). Quantitative measurement of the area fractions of four domain variants in each film system was made using in-situ second harmonic generation measurement while applying an external electric field at room temperature. While the film system (I) showed reversible domain wall motion, the film system (II) snowed some permanent poling after the removal of the external field. Transmission Electron Microscopy revealed a network of low angle grain boundaries of ∼ 1.5–2° misorientation along the substrate cubic axes in the growth plane of the film system (I) and also a network of 6° and 120° walls intersecting these grain boundaries at 45° in the film growth plane. These features were found to be absent in the film system (II). We propose that the observed electric field poling phenomena is due to the pinning of 60° and 120° domain walls by low angle grain boundaries.

Type
Research Article
Copyright
Copyright © Materials Research Society 1998

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References

REFERENCES

1 Gunter, P., Opt. Commun. 11, 285 (1974).Google Scholar
2 Chun, M. K., Goldberg, L., and Keller, J. F., Appl. Phys Lett. 53, 1170 (1988).Google Scholar
3 Gopalan, V. and Raj, R., J. Am. Ceram. Soc. 78, 1825 (1995).Google Scholar
4 Deshmukh, K. G. and Ingle, S. G., J. Phys. D 4, 124 (1971).Google Scholar
5 Gopalan, V. and Raj, R., J. Am. Ceram. Soc. 79, 3289 (1996).Google Scholar
6 Gopalan, V. and Raj, R., J. Appl. Phys. 81, 865 (1997).Google Scholar