Synthesis, Structural, Electrical, and Thermal Studies of ( and ) Ferroelectric Ceramics

Abstract

The polycrystalline ceramic samples of lead barium niobate with general formula Pb 1−x Ba x Nb 2 O 6 (x = 0.0 and 0.4) were prepared by conventional solid state reaction method. The room temperature X-ray diffraction patterns reveal that both of the samples have orthorhombic crystal structure with space group Cm2m. The dielectric constant and dissipation factor were measured as a function of frequency (100 Hz-2 MHz) and temperature (RT-660K). The DC electrical conductivity of both the samples was measured from RT to 660 K. The activation energies calculated from log σ versus 1000/T curves in ferroelectric phase of the compounds are 1.09 eV for pure (x = 0.0) sample and 1.36 eV for Ba-substituted (x = 0.4) sample. The values of activation energies show that the substitution of Ba 2+ ion on Pb 2+ ion site increases the resistivity of pure PbNb 2 O 6 (x = 0.0) ceramic. The modulated differential scanning calorimetry (MDSC) has been used to investigate the phase transition temperature of both the compounds and also to see the effect of Ba 2+ ion substitution on the phase transition temperature, specific heat, and other thermal parameters of the compound.

Dielectric Properties of PbNb2O6 up to 700°C from Impedance Spectroscopy

“…Result from each technique shows expected increase of dc with temperature ( ), as shown in Figure 17. DC activation energy ( dc ) due to DC conductivity [14] was calculated using the empirical Arrhenius relation dc = 0 exp(− dc / ), where is Boltzmann constant, 0 is preexponential factor and dc is the DC activation energy for the conduction process [33][34][35][36], by plotting ln( dc ) versus 1/ . Figure 19 gives this DC activation energy for different temperature ranges, indicated by the horizontal bars, as found independently from cross and peak data, for two-and three-region fits.…”

“…So, higher materials are being developed worldwide for high temperature (HT) applications. Lead metaniobate (PbNb 2 O 6 ), shortened here as PNO, with a higher Curie temperature (517 to 570 ∘ C in different papers), is one of the present candidate materials [2][3][4][5][6][7][8][9][10][11][12][13][14]. It was discovered [3] in 1953.…”