First Principles’ Investigation of Electronic Properties of Hf, Ag, Cd, Zn, Ce, Nd, Sm-Modified Lead Zirconate Titanate

2018 ◽  
Vol 15 (11) ◽  
pp. 3201-3201
Author(s):  
R. K Hussein ◽  
M El-Okr ◽  
I. I Bashter ◽  
M Ibrahim
2016 ◽  
Vol 13 (10) ◽  
pp. 7661-7665
Author(s):  
R. A Hussein ◽  
M El-Okr ◽  
I. I Bashter ◽  
M Ibrahim

First principles investigations, including density functional theory (DFT) have been applied to calculate the electronic properties of A-site modified lead zirconate titanate (PZT). The theoretical explanation for the origin of fatigue in ferroelectric perovskite oxides was implemented to study the fatigue behavior. The explanation indicates that, the fatigue is related to the weakness of π bond between Ti 3d and O 2p states, caused by the occupancy of the Ti 3d state by electrons which released from oxygen vacancies. If a certain energy state of the additive element founded to be overlapped with the Ti 3d state at conduction band minima, then it will sharing the electrons released by oxygen vacancies with the Ti 3d state. Therefore, when the Ti 3d state become less occupied with electrons the π bond between the Ti 3d and O 2p states become more maintained and the composition is less susceptible to fatigue.


2019 ◽  
Vol 27 (1) ◽  
pp. 15-30 ◽  
Author(s):  
Rageh K. Hussein ◽  
Ibrahim I. Bashter ◽  
Mohamed El-Okr ◽  
Medhat Ahmed Ibrahim

Abstract Density of states and geometrical structures of modified Lead zirconate titanate are investigated using density functional theory within local density approximation. The electronic properties and bond length variation have been studied in terms of electronic structure and bonding mechanism principles respectively. Hybridization between Ti 3d - O 2p states and ferroelectric distortion have been addressed as a theoretical approach, to rule the improvement of ferroelectric properties of Lead zirconate titanate. The analysis of Ga, Tl modified Lead zirconate titanate were found to diminish the hybridization between Ti 3d - O 2p states, the relaxed behavior lead to the reversal of the known ferroelectric distortion. Y, Ho, Yb and Lu modified Lead zirconate titanate compounds have a tendency to intense the ferroelectric stability, its exhibit higher hybridization between Ti 3d - O 2p states than pure Lead zirconate titanate, also the arrangement of the ions distortions is strongly the same as the more favoured ferroelectric states of Lead zirconate titanate.


2019 ◽  
Vol 28 (3) ◽  
pp. 034002 ◽  
Author(s):  
Manura Liyanage ◽  
Ronald Miller ◽  
RKND Rajapakse

2007 ◽  
Vol 46 (8A) ◽  
pp. 5199-5204 ◽  
Author(s):  
Yukihiro Okuno ◽  
Koji Kawato ◽  
Masayuki Suzuki ◽  
Akinori Harada ◽  
Tamio Oguchi

Author(s):  
M.L.A. Dass ◽  
T.A. Bielicki ◽  
G. Thomas ◽  
T. Yamamoto ◽  
K. Okazaki

Lead zirconate titanate, Pb(Zr,Ti)O3 (PZT), ceramics are ferroelectrics formed as solid solutions between ferroelectric PbTiO3 and ant iferroelectric PbZrO3. The subsolidus phase diagram is shown in figure 1. PZT transforms between the Ti-rich tetragonal (T) and the Zr-rich rhombohedral (R) phases at a composition which is nearly independent of temperature. This phenomenon is called morphotropism, and the boundary between the two phases is known as the morphotropic phase boundary (MPB). The excellent piezoelectric and dielectric properties occurring at this composition are believed to.be due to the coexistence of T and R phases, which results in easy poling (i.e. orientation of individual grain polarizations in the direction of an applied electric field). However, there is little direct proof of the coexistence of the two phases at the MPB, possibly because of the difficulty of distinguishing between them. In this investigation a CBD method was found which would successfully differentiate between the phases, and this was applied to confirm the coexistence of the two phases.


2020 ◽  
Author(s):  
Dixiong Wang ◽  
Sinan Dursun ◽  
Lisheng Gao ◽  
Carl S. Morandi ◽  
Clive A. Randall ◽  
...  

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