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296 results on '"Laosiritaworn, Yongyut"'

54. Changes in ferroelectric properties of ceramics in lead magnesium niobate–lead titanate system with compressive stress.

Author

Unruan, Muangjai, Wongmaneerung, Rewadee, Ngamjarurojana, Athipong, Laosiritaworn, Yongyut, Ananta, Supon, and Yimnirun, Rattikorn

Subjects
FERROELECTRICITY, CERAMICS, LEAD, MAGNESIUM, NIOBATES, TITANATES, PEROVSKITE, MICROSTRUCTURE
Abstract

Effects of compressive stress on the ferroelectric properties of Pb(Mg1/3Nb2/3)O3–PbTiO3 (PMN-PT) ceramics were investigated. The ceramics with the formula (1-x)Pb(Mg1/3Nb2/3)O3-(x)PbTiO3 or (1-x)PMN-(x)PT (x=0.1–0.5) were prepared by a conventional mixed-oxide method. Dense perovskite-phase PMN-PT ceramics with a uniform microstructure were obtained. The ferroelectric properties were measured under compressive stress (0–75 MPa) using a homebuilt compressometer in conjunction with a modified Sawyer–Tower circuit. The experimental results revealed that the superimposed compression stress significantly reduced both the dissipation energy and the polarizations of the near morphotropic phase boundary compositions, i.e., 0.8PMN-0.2PT, 0.7PMN-0.3PT, and 0.6PMN-0.4PT, while the stress influence was much less in other compositions. On the contrary, the applied compressive stress showed little or no influence on the coercive field. These results were interpreted through the non-180° ferroelastic domain switching processes and the stress induced decrease in the switchable part of domains. [ABSTRACT FROM AUTHOR]

Published
2008
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55. Influences of perpendicular compressive stress on the dielectric and ferroelectric properties of electrostrictive and piezoelectric Pb(Mg1/3Nb2/3)O3-PbTiO3 ceramics.

Author

Unruan, Muangjai, Ngamjarurojana, Athipong, Laosiritaworn, Yongyut, Ananta, Supon, and Yimnirun, Rattikorn

Subjects
DIELECTRICS, FERROELECTRICITY, PIEZOELECTRIC materials, LEAD, NIOBIUM oxide, TITANIUM dioxide, CERAMICS, ELECTRIC fields
Abstract

The dielectric and ferroelectric properties of (1-x)Pb(Mg1/3Nb2/3)O3-(x)PbTiO3 or (1-x)PMN-(x)PT (x=0.1–0.4) ceramics were measured under compressive stress applied perpendicular to the electric field. For the dielectric properties, the experimental results revealed that the superimposed perpendicular compression stress reduced the dielectric constant but increased the dielectric loss tangent of all the compositions. On the other hand, for the ferroelectric properties the applied stress noticeably enhanced the dissipation energy, the polarizations, and the coercive field of all the compositions. These results were interpreted through the non-180° ferroelastic domain switching processes, the stress clamping of domain walls, the deaging mechanism, and the stress induced enhancement in the switchable part of spontaneous polarization. More importantly, the influences of the stress applied in the perpendicular direction to the electric field were generally opposite to those of the parallel stress. [ABSTRACT FROM AUTHOR]

Published
2008
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56. Influences of perpendicular compressive stress on the dielectric and ferroelectric properties of electrostrictive and piezoelectric Pb([Mg.sub.1/3][Nb.sub.2/3])[O.sub.3]-PbTi[O.sub.3] ceramics

Author

Unruan, Muangjai, Ngamjarurojana, Athipong, Laosiritaworn, Yongyut, Ananta, Supon, and Yimnirun, Rattikorn

Subjects
Lead compounds -- Electric properties, Lead compounds -- Structure, Niobium alloys -- Electric properties, Niobium alloys -- Structure, Titanium compounds -- Electric properties, Titanium compounds -- Structure, Physics
Abstract

The dielectric and ferroelectirc properties of (1-x)Pb([Mg.sub.1/3][Nb.sub.2/3])[(O.sub.3]-(x)PbTi[O.sub.3] ((1-x)PMN-(x)-PT) (x=0.1-0.4) ceramics are measured under compressive stress applied perpendicular to the electric field. The influences of the stress applied in the perpendicular direction to the electric field are opposite to those of the parallel stress.

Published
2008

70. First-principles study of structural properties and morphotropic phase boundaries of Ag1-xKxNbO3 solid solutions.

Author

Pramchu, Sittichain, Jaroenjittichai, Atchara Punya, and Laosiritaworn, Yongyut

Subjects
SOLID solutions, DENSITY functional theory, GEOGRAPHIC boundaries, CRYSTAL structure, PIEZOELECTRICITY
Abstract

Density functional theory was used to inspect the structural properties and morphotropic phase boundaries (MPBs) of Ag1-xKxNbO3 (AKN) solid solutions. Structural properties of pristine AgNbO3 in Pbcm and Pmc21 phases were firstly investigated. The obtained crystal structures were found to be in good agreement with those from experiments. From the formation energy calculation of AKN solid solutions, the coexistences between Pbcm and Pmc21 phases and between Bmm2 and Pm phases were found to be in the composition ranges of x<"0.46" and x>"0.46," respectively. Therefore, the MPB separating the antiferroelectric and the ferroelectric phases can be specified at x ≈ "0.46." This theoretical study provides x ≈ "0.46" as a suggestive composition probably useful to acquire superior piezoelectricity for the utilization of AKN with reduced volatility of alkali elements at the A-site. [ABSTRACT FROM AUTHOR]

Published
2018
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89. First-principles investigation of a novel organic-inorganic strontium halide perovskites and CH 3 NH 3 Pb 1-x Sr x I 3 solid solution.

Author

Pramchu, Sittichain, Laosiritaworn, Yongyut, and Punya Jaroenjittichai, Atchara

Subjects
*DENSITY functional theory, *SPIN-orbit interactions, *SEMICONDUCTORS, *BAND gaps, *PEROVSKITE, *SOLAR cells
Abstract

In this work, we used the density functional theory to predict the stability of CH3NH3SrI3by constructing a chemical potential diagram. We found that there are stability regions of CH3NH3SrI3for tetragonal and orthorhombic structures. TheGWapproximation including spin-orbit coupling (SOC) predicted that CH3NH3SrI3is a wide band gap semiconductor. In addition, the structural and optical properties as a function of strontium concentration (x) in CH3NH3Pb1-xSrxI3were also investigated and it displays the linear dependence on concentration. The results indicate the tunability and its potential as an alternative for using lower concentration of lead in organic-inorganic halide perovskite. [ABSTRACT FROM PUBLISHER]

Published
2016
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