Nanoscale piezoresponse studies of ferroelectric domains in epitaxial BiFeO{sub 3} nanostructures.
We report the dependence of the ferroelectric domain configuration and switching behavior on the shape (square versus round) of epitaxial BiFeO{sub 3} (BFO) nanostructures. We fabricated (001) oriented BFO(120 nm)/SrRuO{sub 3}(SRO,125 nm) film layers on (001) SrTiO{sub 3} single crystals by rf magnetron sputter deposition, and patterned them to square (500 x 500 nm{sup 2}) and round (502 nm in diameter) shaped nanostructures by focused ion-beam lithography. The surface morphology and the crystalline structure of the nanostructures were characterized by scanning electron microscopy and x-ray diffraction, respectively, while the domain configuration was investigated using piezoelectric force microscopy. We found that the square-shaped nanostructures exhibit a single variant domain configuration aligned along the [{bar 1}1{bar 1}] direction, whereas the round-shaped nanostructures exhibit seven variants of domain configuration along the [{bar 1}1{bar 1}], [1{bar 1}{bar 1}], [11{bar 1}], [111], [{bar 1}11], [1{bar 1}1], and [{bar 1}{bar 1}1] directions. Moreover, local d{sub 33} piezoelectric coefficient measurements showed hysteresis loops with a strong displacement in the voltage axis (strong imprint) for the square-shaped nanostructures, while the round-shaped ones exhibited more symmetric loops. These findings have critical implications for the development of nanocapacitors for gigabyte to terabyte nonvolatile ferroelectric memories.
- Research Organization:
- Argonne National Laboratory (ANL)
- Sponsoring Organization:
- SC
- DOE Contract Number:
- AC02-06CH11357
- OSTI ID:
- 952920
- Report Number(s):
- ANL/MSD/CP-62224
- Journal Information:
- J. Appl. Phys., Journal Name: J. Appl. Phys. Journal Issue: Mar. 15, 2009 Vol. 105
- Country of Publication:
- United States
- Language:
- ENGLISH
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