| Summary: | 碩士 === 國立中興大學 === 物理學系所 === 102 === The complex impedance of the glasses with composition MO-(50-x) V2O5-50P2O5, where MO is Na2O, Ag2O, CaO or ZnO, and x=10, 20, 30 mol% are measured. The imaginary parts of the impedance spectra display two absorption peaks. One peak at the high frequency region corresponds to the movement of charge carrier, the other peak at the low frequency region attributes to the charge accumulation on the electrode interface. Based on the analysis of the relaxation time of the charge carries, the conducting species is primary polaron for glasses containing CaO and ZnO, while it is primary ion for Ag2O based glasses. However, the predominant conducting species changes from polaron to ion as the content of Na2O increases from 20mol% to 30mol%. The positions of the peaks at the low frequencies region depend on the dc bias that applied. The peaks move to high frequencies by increasing bias voltage for samples with ionic conduction predominantly, while, the peaks move to lower frequencies samples predominant by polaron conduction. The phenomenon is explained by the change of the concentration gradient of the ion at the interface of electrods.
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