scholarly journals DFT Investigation of Structural and Electronic Properties of Modified PZT

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.

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.


2004 ◽  
Vol 830 ◽  
Author(s):  
Hiroshi Nakaki ◽  
Hiroshi Uchida ◽  
Shoji Okamoto ◽  
Shintaro Yokoyama ◽  
Hiroshi Funakubo ◽  
...  

ABSTRACTRare-earth-substituted tetragonal lead zirconate titanate thin films were synthesized for improving the ferroelectric property of conventional lead zirconate titanate. Thin films of Pb1.00REx (Zr0.40Ti0.60)1-(3x /4)O3 (x = 0.02, RE = Y, Dy, Er and Yb) were deposited on (111)Pt/Ti/SiO2/(100)Si substrates by a chemical solution deposition (CSD). B-site substitution using rare-earth cations described above enhanced the crystal anisotropy, i.e., ratio of PZT lattice parameters c/a. Remanent polarization (Pr) of PZT film was enhanced by Y3+-, Dy3+- and Er3+-substitution from 20 μC/cm2 up to 26, 25 and 26 μC/cm2 respectively, while ion substitution using Yb3+ degraded the Pr value down to 16 μC/cm2. These films had similar coercive fields (Ec) of around 100 kV/cm. Improving the ferroelectric property of PZT film by rare-earth-substitution would be ascribed to the enhancement of the crystal anisotropy. We concluded that ion substitution using some rare-earth cations, such as Y3+, Dy3+ or Er3+, is one of promising technique for improving the ferroelectric property of PZT film.


1991 ◽  
Vol 58 (25) ◽  
pp. 2910-2912 ◽  
Author(s):  
Hideo Kidoh ◽  
Toshio Ogawa ◽  
Akiharu Morimoto ◽  
Tatsuo Shimizu

2009 ◽  
Vol 382 (1) ◽  
pp. 49-55 ◽  
Author(s):  
P. Ketsuwan ◽  
Anurak Prasatkhetragarn ◽  
N. Triamnuk ◽  
C. C. Huang ◽  
A. Ngamjarurojana ◽  
...  

2003 ◽  
Vol 18 (12) ◽  
pp. 2882-2889 ◽  
Author(s):  
Naratip Vittayakorn ◽  
Gobwute Rujijanagul ◽  
Tawee Tunkasiri ◽  
Xiaoli Tan ◽  
David P. Cann

The ternary system of lead nickel niobate Pb(Ni1/3Nb2/3)O3 (PNN), lead zinc niobate Pb(Zn1/3Nb2/3)O3 (PZN), and lead zirconate titanate Pb(Zr1/2Ti1/2)O3 (PZT) was investigated to determine the influence of different solid state processing conditions on dielectric and ferroelectric properties. The ceramic materials were characterized using x-ray diffraction, dielectric measurements, and hysteresis measurements. To stabilize the perovskite phase, the columbite route was utilized with a double crucible technique and excess PbO. The phase-pure perovskite phase of PNN–PZN–PZT ceramics was obtained over a wide compositional range. It was observed that for the ternary system 0.5PNN–(0.5 - x)PZN–xPZT, the change in the transition temperature (Tm) is approximately linear with respect to the PZT content in the range x [H11505] 0 to 0.5. With an increase in x, Tm shifts up to high temperatures. Examination of the remanent polarization (Pr) revealed a significant increase with increasing x. In addition, the relative permittivity ([H9280]r) increased as a function of x. The highest permittivities ([H9280]r [H11505] 22,000) and the highest remanent polarization (Pr [H11505] 25 μC/cm2) were recorded for the binary composition 0.5Pb(Ni1/3Nb2/3)O3–0.5Pb(Zr1/2Ti1/2)O3.


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