Dielectric spectroscopy of Pb(Mg1/3Nb2/3)O3-PbTiO3 single crystals

Abstract

Complex impedance spectroscopic data were acquired on single crystals of the morphotropic phase boundary composition of 0.68Pb(Mg1/3Nb2/3)O3-0.32PbTiO3 over a wide range of temperatures (25–525 °C) and frequencies 1 kHz–1 MHz. This study takes advantage of plotting ac data simultaneously in the form of impedance and modulus spectroscopic plots. This permits the easy interpretation of microscopic processes responsible for the measured ac response. Frequency explicit plots of imaginary components of impedance and modulus exhibit Debye-like peak shapes. The data for ac conductivity were computed from the impedance data and the activation energy for conduction at different frequencies was determined. Cole–Cole diagrams were plotted and these indicate the presence of a single relaxation process. The relaxation times determined from these plots followed an Arrhenius law, and the activation energy for relaxation was found to be 1.2 eV. The ac conductivity data was found to obey Jonscher’s universal power law and resulted in a value of the exponent “n”=0.95.

Ferroelectric state analysis in grain boundary of Na0.85Li0.15NbO3 ceramic

“…Moreover, the frequency of the maximum, an apparent relaxation frequency, shifts to more high values with increasing of the temperature. This behavior has been reported for several single crystals 13,14 being evidence of actuation of a hopping type mechanism as small polaron hopping with gradual decrease of electron-lattice coupling.…”

Grain boundary electric characterization of Zn7Sb2O12 semiconducting ceramic: A negative temperature coefficient thermistor

“…Despite the great number of events that can be correlated to further explain the decentralization phenomenon, this phenomenon has been reported to occur in high-quality single crystals of complex sillenite 14 and in perovskite solid-solution 18 structure, as well as in functional glasses. 9,10 Therefore, this phenomenon is not intercorrelated a priori to some kind of quality factor of the material, but is an intrinsic feature of them.…”

Dielectric relaxation and magnetic properties of Cr doped GaFeO3

“…The M /M max curves are overlap for all the temperatures into a single master curve, indicating that they describe the same mechanism at various temperatures relaxations. The temperature dependence of the characteristic relaxation time was determined and plotted in Figure 7 (d), which follows the Arrhenius law [31]. From the least square fitting, the activation energies are calculated, and are found to be 0.22 and 0.27 eV for Cr=10 and 15%, respectively.…”