Polarization contributions to DC bias characteristics of nanograined BaTiO₃-based ceramics

Abstract

The domain configuration contributions to the direct-current (DC) bias characteristics of nanograined BaTiO3 were clarified. Domain boundaries became more ambiguous with decreasing grain size (g.s.), whereas domain patterns partially vanished because of the reduction in BT ferroelectricity, in the g.s. range < 1 μm. Additionally, intergranular stress increased with decreasing g.s., resulting in crystal lattice hardening in the vicinity of the domain walls (DWs) and suppression of dipole fluctuations in the DWs. These domain structural variations with the domain size (d.s.) reduced permittivity in the absence of a DC electric field, resulting in improvements in permittivity depressions in an electric field (Δε). Magnesium substitution slightly decreased the d.s. The increase in DW density upon Mg loading implied defect pairs, which acted as new DW pinning centers, thereby subdividing the DWs. The Δε notably improved via Mg loading, because a defect pair effectively pins the DWs under the electric field.

Inhibition of Oxygen Vacancy Derived from Donor Doping in Relaxor Ferroelectric Films for Improving Dielectric Energy Storage

“…6 The oxygen vacancy not only results in the p-type leakage conductivity and decreased E BDS but also depresses P max due to the domain wall pinning effect originated from the oxygen vacancy. Therefore, decreasing the oxygen vacancy concentration is an important means to enhance E BDS and P max simultaneously, 7,8 and it is also an important way to break through the adverse coupling of the two from another perspective.…”

Polarization at the compositional interface in Nb-doped metastable TiO2-SnO2 solid solutions

“…[5][6][7][8][9][10] The permittivity of ferroelectric possessing macrodomain configurations, however, is notably depressed in the nanograin region, since domain-wall motions are suppressed due to the grain-size effect. [11][12][13][14][15] This phenomenon severely restricts further enhancement of the volumetric capacitance density of ferroelectrics-based MLCCs. Accordingly, investigating size-effect-less nonferroelectric materials that have large polarizability is warranted.…”