Structural and morphological studies, and temperature/frequency dependence of electrical conductivity of Ba_0.97La_0.02Ti_1−xNb_4x/5O₃ perovskite ceramics

Abstract

The frequency- and temperature-dependent conductivity of our polycrystalline perovskite ceramic systems with a composition of Ba0.97La0.02Ti1−xNb4x/5O3 (x = 5, 7 and 10, in mol%) was investigated.

Structural, electrical, and dielectric study of the influence of 3.4% lanthanide (Ln3+ = Sm3+ and La3+) insertion in the A-site of perovskite Ba0.95Ln0.034Ti0.99Zr0.01O3

“…According to this model, the AC conductivity of these samples is due to the addition of a charge carrier at a site that leads to local lattice distortion. 77 On the other hand, we observe that “ n 2” varies inversely with temperature. This observation indicates that correlated barrier hopping (CBH) is the appropriate model to understand the mechanism of charge transport in grain boundaries (region II).…”

“…The presence of the constant phase element in the grains and in the grain boundaries indicates a non-ideal capacitive behavior, and this non-ideal behavior of the grains and grain boundaries may be due to the presence of more than one relaxation process. 77–79 The capacitance C and the phase element value CPE are related as where α < 1. 80,81 Fitted Nyquist plot and the equivalent circuits for the BLaZT composition at different temperatures is presented in Fig.…”

“…If n < 1, it means that the jumping motion involves a translational motion with a sudden jump, while n > 1, it means that the motion involves a localized jump without the species leaving the neighborhood. 56,77 The analysis of the conductivity spectra for the lanthanide-doped (Ln = Sm 3+ and La 3+ ) and undoped BZT compound shows two plateau regions corresponding to the grain (low frequency) and grain boundary (high frequency) contribution and a single power law is not sufficient to explain its conduction mechanism. Therefore, the conductivity behavior of these three systems (BZT, BSmZT and BLaZT) can be explained by the modified Jonscher power law, 58,70 given below. σ ( ω ) = σ ac + A 1 ω n 1 + A 2 ω n 2 where, σ ( ω ) represents the total conductivity, σ dc is the dc conductivity arise, A 1 ω n 1 and A 2 ω n 2 mean the charge carrier transport properties (polarons, electrons and ions) of the grain and the joined grain in the BZT, BSmZT and BLaZT ceramic, respectively.…”

“…Several types of models have been reported by many researchers in the literature. 77 Fig. 12(a) and (b) represents the variation of the parameters "n 1 " and "n 2 " with temperature (300-400 °C) for undoped and Sm and La doped BZT compounds, This observation indicates that the non-overlapping small polaron tunneling effect (NSPT) is the appropriate model to understand the charge transport mechanism in grains (region I).…”

Improved Capacitive Performance and Polarization Sustainability of Silver Stannate Nanoparticles: The Role of Carbon Nitride Incorporation

“…For the ASO-CN system, the variation in the "S" values was observed within the range from 0.81 to 1.2, which implies localized polaron hopping without leaving the neighboring sites (short-range interaction) with the conduction mechanism from SPT to CBH. 46,47 The localized hopping is more significant in the ASO-CN system due to the presence of the carbon nitride structure, where the polarons are trapped at the boundary region of carbon nitride and stannate nanoparticles. The ac conductivity as a function of frequency for the ASO-and ASO-CN-based devices at 30 and 100 °C is plotted (log−log) in Figure S3 (Supporting Information).…”