Aging of the Weak‐Field Dielectric Response in Fine‐ and Coarse‐Grain Ceramic BaTiO₃

Abstract

BaTiO, ceramics with grain sizes of 0.6 to 6 mm and relative densities of 89% to 92% were prepared by hot forging and conventional sintering from high-purity oxalate-derived powder. The aging of both the dielectric constant and the dielectric loss was examined with respect to grain size, temperature, and frequency. It is suggested that the main aging mechanism in coarse-grained BaTiO, is the aging of hysteretic domain wall motion. The dielectric aging is a thermally activated process and shows two aging rates when observed at a temperature of 8°C for coarse-grained ceramics.

Piezoelectric and dielectric aging of Bi0.5(Na0.82K0.18)0.5TiO3 lead-free ferroelectric thick films

“…Figure 3 illustrates the normalized aging curves for remanent polarization, dielectric constant and piezoelectric coefficient of poled NKBT thick films with the ac fields of 1 and 10 kV/cm ͑1 kHz͒ at room temperature. 18 As reported by Koh et al 27 and Wu and Schulze, 28 the dielectric and piezoelectric aging rate for bulk ceramics increased with the increasing ac amplitude, which is associated with the increased motion of domain walls and their dependence on the internal bias produced by reorientating defect dipoles. The similar aging behaviors of dielectric and piezoelectric are in perfect concordance with that of the bulk ceramics.…”

Dielectric Properties of Fine Grains Barium Titanate Ceramics Prepared by Mechanochemical Synthesis

“…The grain size increases rather steadily with increasing temperature. The dielectric properties of the fine and coarse grains samples of BaTiO3 are shown in figures 6 and 7. Figure 6 shows the behavior of the relative dielectric constant as a function of the grain size.…”

“…The characteristics of this electronic ceramic are markedly influenced by the technological parameters used in processing the ceramic powder especially by the particle size, and morphology [3]. Dielectric constant for example is strongly dependent on the grain size [4][5][6][7][8]. For coarse grained ceramics the dielectric constant at room temperature is lower than for fine grained ones [9,10].…”

Harmonic Analysis of Polarization Hysteresis of Aged PZTs

“…From these figures, it can be seen that K wf , k p , and d 33 decreased (aged) as a linear function of log time. The aging behavior follows the logarithmic law, and an aging equation can be written as follows 8 : where P i is the property, e.g., K wf , k p , and d 33 at the beginning of the test (time equal to zero). The relative aging rate is expressed as …”

“…Aging is defined as the spontaneous decrease of a property with time, under zero external electric field and isothermal conditions 1 . Most studies of aging in PZTs have concentrated on the aging in the relative dielectric constant and other dielectric properties under weak‐field; many models for this aging have been proposed 2–9 . However, there is no universally accepted model to describe the mechanisms of aging.…”