Two-level hierarchical stripe domains and enhanced piezoelectricity of rapid hot-press sintered BiFeO3 ceramics

Abstract

BiFeO3 represents the most extensively investigated multiferroic due to its fascinating ferroelectric domain structures, large polarization, and multiferroic coupling, among many other emergent phenomena. Nevertheless, much less concern with the piezoelectricity has been raised while all these well addressed properties are identified in thin film BiFeO3, and bulk ceramic BiFeO3 has never been given priority of attention. In this paper, we report our experiments on the ferroelectric and piezoelectric properties as well as domain structures of BiFeO3 bulk ceramics synthesized by rapid hot-press sintering. It is revealed that these properties are strongly dependent on the microstructural quality, and the largest piezoelectric coefficient d33 = 55 pC/N with electric polarization as large as 45 μC/cm2 is obtained for the sample sintered at 800 °C, while they are only 30 pC/N and 14 μC/cm2 for the samples sintered in normal conditions at 800 °C. The two-level hierarchical stripe-like and irregular dendrite-like domain structures are observed in these hot-press sintered samples. It is suggested that the enhanced piezoelectric property is ascribed to the two-level hierarchical stripe-like domain structure which may respond more easily to electrical and strain stimuli than those irregular dendrite-like domains. The enhanced remnant polarization should be owing to the improved sample quality and large grains in the properly hot-press sintered samples.

Ultra‐high‐temperature piezoelectric responses and ultra‐high thermal stability of piezoelectricity in ceramic PbZr0.54Ti0.46O3

“…The A‐site Pb vacancies ($${\rm{V}}_{{\rm{Pb}}}^{^{\prime\prime}}$$) reduce the inner stress and increase the 90° domain wall mobility, which improves the piezoelectric and electromechanical responses 15 . The stripe domain structure easily responds to electrical stimuli, since the stripes can easily move and align along the electric field 35 . This explains the multiple right‐angle connections of stripes in the 1.0Nd‐PZT.…”

“…15 The stripe domain structure easily responds to electrical stimuli, since the stripes can easily move and align along the electric field. 35 This explains the multiple right-angle connections of stripes in the 1.0Nd-PZT.…”

A metalloprotein-inspired thermo-gene for thermogels

“…The thermo-gene is the coordinating hydrogel formed with folate and zinc ions (Scheme 1a). Previous work verified that the coordination between the carbonate groups of the folate and Zn 2+ ions in water would lead to printable hydrogels, 29 where the folate ions form tetramers, which further stack into fibers via π-π interactions. These fibers were then cross-linked by the coordination between Zn 2+ and the carboxylate groups on the fiber surface to form bundles and physical networks 29 (Scheme 1a).…”

“…Previous work verified that the coordination between the carbonate groups of the folate and Zn 2+ ions in water would lead to printable hydrogels, 29 where the folate ions form tetramers, which further stack into fibers via π-π interactions. These fibers were then cross-linked by the coordination between Zn 2+ and the carboxylate groups on the fiber surface to form bundles and physical networks 29 (Scheme 1a). In this work, we show that the thermo-gene itself is a TG, and this TG remains stable even at a high temperature of 90°C.…”