Abstract
Fourier transform infrared (FTIR) spectrum dielectric constant, epsilon', loss tangent, tan(delta), electric modulus, M*, and ac conductivity, sigma(ac), of pure polyvinyl alcohol (PVA) as well as La-, Gd-, and Er-PVA doped samples have been carried out. The dielectric properties have been studied in the temperature and frequency ranges; 300-450 K and 1 kHz-4 MHz, respectively. FTIR measurements reveal that La3+, Gd3+, and Er3+ ions form complex configuration within PVA structure. Two relaxation processes, namely, rho and alpha were observed in pure PVA sample. The first process is due to the interfacial or Maxwell-Wagner-Sillers polarization. The second one is related to the micro-Brownian motion of the main chains. For doped PVA samples, alpha-relaxation process splits into alpha(a) and alpha(c). This splitting is due to the segmental motion in the amorphous (alpha(a)) and crystalline (alpha(c)) phases of PVA matrix. Electric modulus analysis was discussed to understand the mechanism of the electrical transport process. The behavior of ac conductivity for all PVA samples indicates that the conduction mechanism is correlated barrier hopping. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4739752]