Moumita Khutia; Girish M. Joshi; Subhratanu Bhattacharya
Abstract
Polyvinyl alcohol (PVA) /Poly (tetrafluoroethylene) (PTFE)/Titanium oxide (TiO2) was prepared by ( 5, 10 and 15 wt %) TiO2 loading. The miscibility, thermal property and microstructure of the composites were characterized by differential scanning calorimetry (DSC) and scanning electron microscopy ...
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Polyvinyl alcohol (PVA) /Poly (tetrafluoroethylene) (PTFE)/Titanium oxide (TiO2) was prepared by ( 5, 10 and 15 wt %) TiO2 loading. The miscibility, thermal property and microstructure of the composites were characterized by differential scanning calorimetry (DSC) and scanning electron microscopy (SEM). The electrical relaxation dynamics including dielectric and electrical conductivity was examined as a function broadband of frequency and temperature. The dielectric data was analyzed via the electric modulus. The Maxwell-Wagner-Siller (MWS) effect corresponds to interfacial polarization at low frequency follows Arrhenius behavior. The α-mode relaxation is attributed to glass-rubbery transition in composites, obeys the Vogel- Taman-Fulcher (VTF) model. A slight bump was noted at relatively high temperature and high frequencies termed as Intermediate dipolar effect (IDE) obeys the Arrhenius behavior. Conductive mechanism was analyzed via AC conductivity spectra. However, DC conductivity follows Arrhenius equation. The overall studies confirm that the self relaxation mechanism of PVA/PTFE composites were modified by TiO2, offers the tuning conductivity as a function of the temperature which can be used in various electronic applications.
Nawnit Kumar; Patri Tirupathi; Bineet Kumar; Mukul Pastor; A. C. Pandey; R. N. P. Choudhary
Abstract
We reports structural, microstructural and dielectric characteristics of Sr 2+ doped PZT (50/50) ceramic. X-ray diffraction reveals that the system exhibit coexistence of two phases (Tetragonal and rhombohedral) at room temperature. Typical relaxor behavior was observed by the dielectric studies and ...
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We reports structural, microstructural and dielectric characteristics of Sr 2+ doped PZT (50/50) ceramic. X-ray diffraction reveals that the system exhibit coexistence of two phases (Tetragonal and rhombohedral) at room temperature. Typical relaxor behavior was observed by the dielectric studies and confirmed by Vogul-Fulcher fitting. The observed relaxor was predicted as existence of nanopolar regions due to short range ordering in presence of oxygen vacancies. The evidence for oxygen vacancies was studied by conductivity and polarization studies. Moreover, at 270 °C one more phase transition is noted which was ascribed to structural phase transition. Present study has scientific significance to distinguish the performance of oxygen vacancies in ferroelectric materials.
