Abstract
Strontium bismuth tantalate thin films having composition of Sr0.7Bi2.4Ta2O9 (SBT) were deposited on the pre-crystallized SBT seed layer with the same composition using sol-gel and spin coating methods. Unseeded and seeded SBT thin films were crystallized to fluorite by heating at 600°C for 1h and they were further heated in the range of 710-740°C at 10°C intervals for different time periods to analyze fluorite-to-Aurivillius phase transformation characteristics. X-ray diffraction (XRD) results on the heated films indicate that the phase transformation kinetics is greatly enhanced in the seeded ones. Quantitative X-ray diffraction (Q-XRD) was performed and the results were used for Johnson-Mehl-Avrami (JMA) isothermal kinetic analyses. From JMA plots Avrami exponent values for unseeded and seeded films were determined as ∼1.5 and ∼1.1, respectively, which implies that each film has a different nucleation mechanism. Using Arrhenius plots the activation energy values for the phase transformation of unseeded and seeded films were determined as ∼263 and ∼183 kJ/mol, respectively. The nucleation mechanism difference and the resultant activation energy difference provide the origin of enhanced kinetics in seeded SBT thin films.
Original language | English |
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Pages (from-to) | 92-99 |
Number of pages | 8 |
Journal | Journal of Crystal Growth |
Volume | 254 |
Issue number | 1-2 |
DOIs | |
Publication status | Published - 2003 Jun |
Externally published | Yes |
Keywords
- A1. Phase transformation
- A3. Sol-gel
- B2. Ferroelectric materials
ASJC Scopus subject areas
- Condensed Matter Physics
- Inorganic Chemistry
- Materials Chemistry