Papers by Keyword: PbTiO₃

Abstract: PbTiO₃ is one of electroceramic materials which can be applied for electronics and microelectronics due to their dielectric, pyroelectric, and piezoelectric properties. The members of PbTiO₃-based ferroelectrics are widely used in multilayer, actuator and sensor capacitor. At room temperature, PbTiO₃ has a tetragonal perovskite structure. In this research, PbTiO₃ particles are synthesized by mechanical alloying method with variation of milling time and sintering temperature. The milling time variation is taken for 10, 20 and 30 hours. Sintering temperature variation is performed at 850, 900 and 1000°C. The powders used in the milling process are PbO and TiO₂ powders. X-Ray Diffraction (XRD) and Scanning Electron Microscopy–Electron Difraction X-ray (SEM-EDX) are performed to analyze the formation of PbTiO₃ phase. It is found that the synthesized powders contain 100% PbTiO₃ phase for all sintering temperatures. The PbTiO₃ particles have agglomeration shape with a broad particle size. The electrical properties of PbTiO₃ are measured using electrical test device. Electricity test analysis shows that the synthesized PbTiO₃ behaves as semiconductor-like.

Abstract: PbTiO₃ (PTO) films were successfully fabricated by sol-gel method. We studied the structure and the nanoscale polarization switching property using XRD and Piezoresponse Force Microscopy. The results reveal that the PTO films are single perovskite phase grain films with tetragonal structure, and are polycrystalline materials with no evidence of preferential orientation. The average grain size is about 150nm and a striped multi-domain structure is exhibited in individual grains. Under 15 kHz alternating current of PFM, a significant asymmetry of switching pattern was observed. We suggest that the cooperative action of the built-in electric field at the bottom interface and the PFM ac-voltage lead to the asymmetry switching.

Abstract: We have elucidated the elastic interaction between the 90° domains and misfit dislocations in PbTiO₃/SrTiO₃ (001) epitaxial thin films by the local strain mapping based on high-resolution transmission electron microscopy. The novel mechanism of the nucleation and growth of 90 ̊ domain has been proposed based on the results, including the introduction of the additional dislocation perpendicular to the misfit dislocation and the dissociation of these dislocations into two pairs of partial dislocations with an anti-phase boundary.

Abstract: Pre-perovskite PbTiO₃ nanofibres were synthesized by hydrothermal method with four butyl titanate ((C₄H₉O)₄Ti) and lead nitrate (Pb (NO₃)) as the main precursors and Tetramethylammonium Hydroxide (TMAH) as mineralizer. X-ray diffraction (XRD), Raman, Scanning Electronic Microscopy (SEM), Transmission electron microscopy (TEM), high-resolution TEM (HRTEM), and the corresponding selected area electron diffraction (SEAD) were used to characterize the crystal structure and morphology of the obtained products. The results showed that the nanofibers are of a few to tens micrometer at length size, and 50~300 nm at diameter size. Based on the experimental results, the effect of Tetramethylammonium Hydroxide (TMAH) was simply discussed.

Abstract: Perovskite lead titanate crystals with various morphologies were successfully synthesized via a hydrothermal reaction route with different lead sources. X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM) were employed to characterize the phase composition and the morphology of the synthesized products. In order to investigate the effect of the lead source on the phase formation and morphology evolution of the synthesized pervoskite PbTiO₃ crystals, PbO, PbF₂, PbSO₄ and Pb (CH₃COO)₃ ·3H₂O, were used as starting precursor lead source introduced into the hydrothermal reaction system, respectively. Accordingly, perovskite PbTiO₃ brken cubes, irregular particles, cubic particles, and microplates were obtained, respectively. Based on the experimental results, the effect of lead source was simply discussed.

Abstract: _{Subscript text}PbTiO₃ nanometre material with distinct crystal phase were synthesized selectively with different Na₂Ti₄O₉ precursors and their photocatalytic activities were investigated for 2-propanol degradation in gas phase.

Abstract: PbTiO₃ crystals with different morphologies, such as flower-like and spherical shape, which was constructed by oriented nanoparticles have been obtained by a simple surfactant-free hydrothermal process assisted by K₂CO₃ as a mineralizer. Powder X-ray diffraction (XRD) analysis was applied to examine the purity and crystallinity of the as-prepared samples. The morphologies have been characterized by scanning electron microscopy (SEM). The results indicated that the self-assembly structures of PbTiO₃ crystals were dependent on the addition amount of K₂CO₃ and the formation mechanism of the products was briefly discussed.

Abstract: Using polymer as a surfactant, we successfully synthesized of PbTiO3 crystals with a self-assembly structure by a hydrothermal process. The as-obtained powders were characterized by X-ray powder diffraction (XRD) and scanning electron microscopy (SEM). The results show that the presence of PVP, PEG and PVA plays a key role on the formation of self-assembly structure and the corresponding formation mechanism was briefly discussed.

Abstract: A series of ferroelectric superlattice films on ITO substrates have been artificially fabricated by radio frequency magnetron sputtering, starting from the PbZrO3 (PZO) and PbTiO3 (PTO) matrix targets. The design sequence of the layers has been changed via shifting sputtering target in the preparing processes. Diverse systems have been shaped and discussed by XRD, SEM and UV-Vis. UV-Vis absorption spectra have been paid more attention especially, due to the low-cost and non-destructive method to provide the information about the thicknesses of the films.

Abstract: The ferroelectric domain structure of PbTiO₃ (PTO) films was investigated by using transmission electron microscopy (TEM). In the film with PTO/SrTiO₃ (STO) structure, 180º domains are formed near the SrTiO₃ (STO) substrate and the domain length of 180º domains is 100 nm. However, 180º domains are not formed in the film with Pt/PTO/SrRuO₃ (SRO)/STO structure. These results show that 180º domains are formed in order to minimize depolarizing field energy, and that the domain length of 180º domains is determined by the competition among the depolarizing field energy, domain wall energy, Coulomb interaction and elastic interaction.