Giant room temperature compression and bending in ferroelectric oxide pillars

Abstract

Plastic deformation in ceramic materials is normally only observed in nanometre-sized samples. However, we have observed high levels of plasticity (>50% plastic strain) and excellent elasticity (6% elastic strain) in perovskite oxide Pb(In1/2Nb1/2)O3-Pb(Mg1/3Nb2/3)O3-PbTiO3, under compression along <100>pc pillars up to 2.1 μm in diameter. The extent of this deformation is much higher than has previously been reported for ceramic materials, and the sample size at which plasticity is observed is almost an order of magnitude larger. Bending tests also revealed over 8% flexural strain. Plastic deformation occurred by slip along {110} <1$$\bar{1}$$ 1 ¯ 0 > . Calculations indicate that the resulting strain gradients will give rise to giant flexoelectric polarization. First principles models predict that a high concentration of oxygen vacancies weaken the covalent/ionic bonds, giving rise to the unexpected plasticity. Mechanical testing on oxygen vacancies-rich Mn-doped Pb(In1/2Nb1/2)O3-Pb(Mg1/3Nb2/3)O3-PbTiO3 confirmed this prediction. These findings will facilitate the design of plastic ceramic materials and the development of flexoelectric-based nano-electromechanical systems.

Piezoelectric built-in electric field advancing TiO2 for highly efficient photocatalytic air purification

“…17,23,26,27 The peaks at 1335 cm À1 is shied to 1334 cm À1 , and 844 cm À1 is shied to 849 cm À1 aer the hot-stretching, conrming the presence of a polarization eld. 28 The stress-strain curves further reveal the occurrence of phase transformation over TiO 2 /PVDF even at smaller tensile stress 13 -compared to that of PVDF (Fig. 1d).…”

“…And the number of isolated hydroxyl groups is not sufficient or stable during the reaction, and is unsatisfactory with the demand of adsorption and degradation of gaseous organic molecules. [13][14][15] On the other hand, polyvinylidene uoride (PVDF) as a ferroelectricity material can produce a polarization eld via the electro-negative difference between F (À) and H (+) atomic layers. [16][17][18][19] Moreover, the fabrication of exible polarized PVDF is favorable for embedding photocatalysts particles.…”

The Rising of Flexible and Elastic Ceramic Fiber Materials: Fundamental Concept, Design Principle, and Toughening Mechanism

“…There are fewer grain junctions where different grain transformation stresses compete in an oligocrystalline or even single crystalline sample, which exhibits excellent elasticity. [ 5b ] Liu et al [ 2 ] precisely controlled the size of ferroelectric oxide production and obtained columnar samples with excellent elasticity, as shown in Figure a, where a bent cantilever beam had a flexural strain of 8.2% and maximal elastic strains of >6% and >50% during compression, respectively. The first‐principles simulation was further used to describe the effect of microstructure.…”

“…Reproduced with permission. [ 2 ] Copyright 2020, Springer Nature. b) First‐principles atomistic investigation.…”

“…[ 1 ] However, both covalent and ionic bonds are directional, thus limiting the slip of atoms and preventing any ductile behavior at the macroscopic level. [ 2 ] As such, ceramics are brittle in nature, which severely hinders their use in the complex environments. For example, the hypersonic vehicles are generally faced with a high‐frequency vibration environment, while the wearable electronics are usually operated under a high‐intensity bending environment, so their ceramic components (thermal insulation systems of the former, and flexible solid‐state batteries in the latter) are the most vulnerable parts in these cases.…”