| Autor: |
Pignolet, A., Schäfer, C., Satyalakshmi, K.M., Harnagea, C., Hesse, D., Gösele, U. |
| Předmět: |
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| Zdroj: |
Applied Physics A: Materials Science & Processing; 2000, Vol. 70 Issue 3, p283, 9p |
| Abstrakt: |
Thin films of bismuth-layered perovskites such as SrBi[sub 2] Ta[sub 2] O[sub 9] , Bi[sub 4] Ti[sub 3] O[sub 12] , and BaBi[sub 4] Ti[sub 4] O[sub 15] with preferred orientations were grown by pulsed laser deposition on epitaxial conducting LaNiO[sub 3] electrodes on single-crystalline (100) SrTiO[sub 3] or on top of epitaxial buffer layers on (100) silicon. A morphology and structure investigation by X-ray diffraction analysis, scanning probe microscopy, and scanning and transmission electron microscopy showed that the films consisted of both c-axis-oriented regions and mixed (110)-, (100)-, and (001)-oriented regions. The regions with mixed orientation featured rectangular as well as equiaxed crystalline grains protruding out of a smooth c-oriented background. A closer examination revealed that the regions with mixed orientation actually consisted of a c-axis-oriented sublayer growing directly on the epitaxial LaNiO[sub 3] electrode, on top of which the growth of either (110)-, (100)-, or (001)-oriented grains took place. Macroscopic as well as microscopic measurements of the ferroelectric properties of regions with pure c-orientation and of regions with mixed orientations showed a clear relationship between their ferroelectric properties and their morphology and crystallographic orientation. In the regions with mixed orientation, the films exhibited saturated ferroelectric hysteresis loops with well-defined remnant polarisation P[sub r] and coercive field E[sub c] . The regions having c-axis orientation with a smooth surface morphology in contrast exhibited a linear P-E curve with no hysteretic behaviour for SrBi[sub 2] Ta[sub 2] O[sub 9] and BaBi[sub 4] Ti[sub 4] O[sub 15] and a weak ferroelectric behaviour for Bi[sub 4] Ti[sub 3] O[sub 12] . This clearly showed that the ferroelectric properties of bismuth-layered ferroelectric oxides depended on the crystalline orientation of the film and that the observed ferroelectric hysteresis loops in SrBi[sub 2]... [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
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