A review is given on the structural phase transition of hexagonal type BaTiO3 at 222 K and on the ferroelectric 路 ferroelastic phase transition at 70 K. X-ray studies and Raman studies have disclosed that an E2u phonon mode condenses below 222 K where crystal changes from hexagonal P63/...
Structural phase transitions in donor doped BaTiO3 and effects on PTCR behavior[J].Ferroelectrics 1996,177(01).Roseman R D,Kim J,Buchanan R C.Structural phase transition in donor-doped BaTiO3 and effects on PTCR properties. Ferrielectrics . 1996...
structural phase transitionrefractive indicesSellmeier relationspontaneous birefringence222 KThe refractive indices n of the hexagonal type BaTiO3 have been measured. The crystal is optically positive (na = 2.31, nc = 2.39) at 20°C, and the Sellmeier relation holds: n2 1 = S0λ20(1 λ20gl2)...
Precise and simultaneous measurements of thermal, electrical, and acoustic properties were carried out at the 403K phase transition in BaTiO 3 single crystal grown by the top-seeded solution growth method. It has been clarified that the exothermic heat at the transition on cooling has more useful...
Qualitative considerations on the statistics of the phase transition in BaTiO3-type ferroelectrics. In Fizika Dielektrikov; Skanavi, G.I., Ed.; Akad. Nauk SSR: Mascow, Russia, 1960; pp. 290-294.Anderson, P. W. Qualitative Considerations on the Statistics of the Phase Transition in BaTiO3...
A polarizing microscope is used to investigate the ferroelectric phase transition of hexagonal type BaTi03. Extinction positions of thin crystal c-plates change rather steeply with temperature in the ferroelectric phase near the Curie point of Tc 70K. suggesting that a cooperative phenomenon is taking...
The precursor structural modulation of BaTiO3 is studied in the vicinity of the structural phase transition at about 120°C with a polarizing microscope. It is found that there are two kinds of precursor distortions, mainly characterized by lozenge patterns and stripe patterns in the tetragonal phas...
The calculated phase sequence, transition temperatures, latent heats, and spontaneous polarizations are all in good agreement with experiment. The order-disorder vs.\ displacive character of the transitions and the roles played by different interactions are discussed. 展开 关键词:...
phase ransi ion ; sol-gelme hod BatiO 是电子陶瓷中使用最广泛的材料之一, 如陶瓷电容器、正温度系数电阻( posi ive empera urecoefficien resis ance , PtCR )陶瓷热敏元件、铁 电压电器件等都是以 BatiO 为基础材料制作 的 [ 1!4 ] .BatiO 是一种典型的钙钛矿相铁电体,它 在 9K 发生由立方相到四...
The phase transition temperature saturated below a certain layer thickness because, they claimed, interlayer coupling was taking place. In this work, we investigate, by X-ray diffraction and Raman spectroscopy, to temperatures well above the PTO bulk value of 493°C, three anomalously structured a...