Evidence of M-type oxygen octahedral rotations in the high-temperature rhombohedral ferroelectric phase region of Pb(Zr0.95Ti0.05)O3

Abstract

Evidence of M-type oxygen octahedral rotations has been observed by transmission electron microscopy in the high-temperature rhombohedral ferroelectric (FER(HT)) state of Pb(Zr0.95Ti0.05)O3. 1/2{110} superlattice reflections were found to develop on cooling through the dielectric maximum. With further cooling (accompanying a ferroelectric-antiferroelectric transformation), a gradual transition from 1/2{110} to 1/2{111} reflections was observed. We believe this gradual transition is due to a transformation from M-type to R-type octahedral tilts on cooling. Lattice imaging in the FER(HT) state at room temperature revealed a one dimensionality in the 〈110〉 structural modulations. The size of the ordered regions was ∼50–100 Å.

Domain variance and superstructure across the antiferroelectric/ferroelectric phase boundary in Pb1−1.5xLax(Zr0.9TiM0.1)O3

“…However, the concept of in-phase rotational displacements (tilting) giving rise to 1 ⁄2{hk0} p reflections, as suggested by Dai et al [11][12][13] and Watanabe and Koyama, 19 is flawed unless an explanation can be found for their presence in 〈110〉 p zones. It is more likely that they arise from cation displacements for which the condition h k in magnitude does not apply (Sec.…”

“…Pc has sufficient degrees of freedom on the O sites to allow antiphase rotations around all three pseudocubic axes in a manner consistent with tilt system no. 13 Fig. 13.…”

“…[11][12][13] The latter structural distortion was considered by the authors of Refs. 11 and 12 to give rise to 1 ⁄2{hk0} reflections in the FE phase.…”

A neutron diffuse scattering study of PbZrO3and Zr-rich PbZr1–xTixO3

“…Density functional theory calculations show that, with the oxygen octahedral tilts included, the AFE Pbam state and an FE R3c state are very close in energy (Reyes-Lillo & Rabe, 2013;Íñ iguez et al, 2014). The compositional phase boundary between the AFE and FE phases in the PZT phase diagram is around x = 0.07 (Woodward et al, 2005 (Xu et al, 1995; have found evidence for M-type distortions (labelled M þ 3 ), which would imply tilts occurring in phase on successive layers. At high temperature, the cubic phase is considered to be the simplest structure in the perovskite family, with all the atoms at special positions fixed by the crystallographic symmetry.…”

Методика Исследования Рассеяния Рентгеновского Излучения В Монокристаллах В Широком Интервале Температур При Приложении Электрического Поля-=sup=-*-=/Sup=-

“…Возникновение данных сверх-структурных рефлексов может быть связано как с софаз-ными вращениями кислородных октаэдров [14], так и с антипараллельными смещениями ионов свинца [15]. При помощи дифракции электронов было обнаружено, что в окрестности M-точек наблюдаются дополнительные сателлитные рефлексы, существование которых авторы объяснили наличием антифазных доменных границ в антипараллельных смещениях ионов свинца [14]. Образцы для измерений имели вид тонкой пластинки с размерами 30 × 200 × 1000 µm с направлением длин-ной оси [110] в кубических координатах.…”