Abstract
Thick films of polyvinylidene fluoride/trifluoroethylene (P(VDF-TrFE) copolymer with the composition 80/20 mol-% were poled at elevated temperature. The dielectric spectrum of this film shows two resonance peaks which correspond to the fundamental and second harmonic of the thickness vibration mode. Even harmonics of the thickness mode are usually not observed as they are not coupled to the electrical excitation. Piezoelectric and pyroelectric profiling experiments using both the pressure wave propagation (PWP) method and the laser intensity modulation method (LIMM) show that the copolymer has an inhomogeneous polarization profile which leads to the observed second order harmonic. In particular, these methods indicate that an unpoled region exists near the cathode side of the sample. By fitting the observed dielectric spectrum to a model of two Lorentz oscillators, the oscillation strengths have been estimated and found to be consistent with those obtained from the appropriate Fourier coefficients of the measured pyroelectric profile.
| Original language | English |
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| Title of host publication | Proceedings - International Symposium on Electrets |
| Publisher | IEEE |
| Pages | 279-284 |
| Number of pages | 6 |
| Publication status | Published - 1 Dec 1996 |
| Externally published | Yes |
| Event | Proceedings of the 1996 IEEE 9th International Symposium on Electrets, ISE 9 - Shanghai, China Duration: 25 Sept 1996 → 27 Sept 1996 |
Conference
| Conference | Proceedings of the 1996 IEEE 9th International Symposium on Electrets, ISE 9 |
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| Country/Territory | China |
| City | Shanghai |
| Period | 25/09/96 → 27/09/96 |
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Electrical and Electronic Engineering
- Materials Chemistry