Preparation and Size Effect in Pure Nanocrystalline Barium Titanate Ceramics

Domain Wall Displacement is the Origin of Superior Permittivity and Piezoelectricity in BaTiO3 at Intermediate Grain Sizes

“…It can be seen that all the three Bragg reflections can be fit with three symmetric pseudo-Voigt profiles. This result could imply that the additional peak in 14 the middle of this diffraction profile is a single reflection, although any additional subtle peak splitting may not be resolved within the available instrumental resolution. The field-induced peak in the middle of the {002} diffraction profile is therefore interpreted as a different polymorphic phase of unknown symmetry.…”

“…In polycrystalline ferroelectrics, size effects are chiefly evident in materials properties such as the relative dielectric permittivity ( r ) and piezoelectric coefficients (e.g., d 33 and d 31 ). For polycrystalline barium titanate (BaTiO 3 ), the effect of grain size on the relative permittivity has been extensively reported over the past decades [3,4,[6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] and is of particular relevance to the continuous size reduction of BaTiO 3 capacitors. Within the grain size range of 1-10 µm, it is now widely accepted that  r of polycrystalline BaTiO 3 increases with decreasing grain size, reaching a value of 5000, or higher, as the grain size approaches 1 µm.…”

Образование новых структурных состояний в прессованных нанопорошках BaTiO-=SUB=-3-=/SUB=-

“…Кроме того, положение пикового значения DSC-кривой, характеризующее температуру фазового перехода, сместилось в низкотемпературную область. Последнее соответствует диаграмме состояния температур фазовых переходов от размера кристалли-тов, представленных в классической работе [21]. Таким образом, наряду с известным влиянием размера кристал-литов на температуры и кинетику фазовых переходов в титанате бария значительную роль на параметры переходов играет и совершенство структуры отдельных кристаллитов.…”

Block copolymer/ferroelectric nanoparticle nanocomposites

“…Detailed crystal structure renement indicates that these BaTiO 3 NPs are largely tetragonal, with some detectable amounts of orthorhombic phase. 33 We note that theoretical and experimental studies [34][35][36] have been conducted on BaTiO 3 in order to identify the critical size, below which BaTiO 3 retains its cubic paraelectric structure at room temperature, yet there has still been no consensus on this issue. [36][37][38][39] Clearly, our results are in accordance with reports where the critical size of BaTiO 3 NPs was estimated to be on the order of 10-20 nm.…”