Abstract
We report the dependence of the ferroelectric domain configuration and switching behavior on the shape (square versus round) of epitaxial BiFeO 3 (BFO) nanostructures. We fabricated (001) oriented BFO (120 nm) / SrRuO3 (SRO,125 nm) film layers on (001) SrTiO3 single crystals by rf magnetron sputter deposition, and patterned them to square (500×500 nm2) 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 [1̄ 1 1̄] direction, whereas the round-shaped nanostructures exhibit seven variants of domain configuration along the [1̄ 1 1̄], [1 1̄ 1̄], [11 1̄], [111], [1̄ 11], [1 1̄ 1], and [1̄ 1̄ 1] directions. Moreover, local d 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.
| Original language | English (US) |
|---|---|
| Article number | 061619 |
| Journal | Journal of Applied Physics |
| Volume | 105 |
| Issue number | 6 |
| DOIs | |
| State | Published - 2009 |
Funding
The submitted manuscript has been created by UChicago Argonne, LLC, Operator of Argonne National Laboratory (“Argonne”). Argonne, a U.S. Department of Energy Office of Science laboratory, is operated under Contract No. DE-AC02-06CH11357. The U.S. Government retains for itself, and others acting on its behalf, a paid-up nonexclusive irrevocable worldwide license in said article to reproduce, prepare derivative works, distribute copies to the public, and perform publicly and display publicly, by or on behalf of the Government. The FIB nanofabrication was done at the Center for Nanoscale Materials User Facility that is supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02–06CH11357. The X-ray diffraction facility at NU is supported by MRSEC Grant No. DMR-0520513 from the National Science Foundation. The authors gratefully acknowledge the discussion on the manuscript with D. Fong, M. Pan, and R. Nath at Argonne National Laboratory.
ASJC Scopus subject areas
- General Physics and Astronomy