scholarly journals Influence of KF substitution on the ferroelectric phase transition of lead titanate single crystals studied by Brillouin light scattering

2015 ◽  
Vol 05 (02) ◽  
pp. 1550011
Author(s):  
Seonhyeop Shin ◽  
Jae-Hyeon Ko ◽  
Shinya Tsukada ◽  
Yukikuni Akishige ◽  
Krystian Roleder ◽  
...  
Keyword(s):  
Phase Transition ◽  
Light Scattering ◽  
Lead Titanate ◽  
Ferroelectric Phase Transition ◽  
Ferroelectric Phase ◽  
Paraelectric Phase ◽  
Dielectric Measurements ◽  
Brillouin Light Scattering ◽  
Acoustic Damping ◽  
Lower Temperature

The elastic properties of KF-substituted perovskite lead titanate ( PbTiO 3) were investigated by dielectric measurements and Brillouin light scattering. The ferroelectric phase transition occurred at substantially lower temperature due to KF substitution, which was attributed to the modification of the covalency in Pb – O and Ti – O bonds. The longitudinal acoustic (LA) mode of KF-substituted PbTiO 3 showed a frequency softening in the paraelectric phase, which was accompanied by increasing acoustic damping. This indicated that polarization fluctuations responsible for the acoustic anomalies were enhanced by KF substitution.

Effect of donor doping in B sites on the electrocaloric effect of BaTi1−xNbxO3 ceramics

RSC Advances ◽  
2015 ◽  
Vol 5 (88) ◽  
pp. 71873-71877 ◽  
Author(s):  
Yang Bai ◽  
Xi Han ◽  
Li-Jie Qiao
Keyword(s):  
Phase Transition ◽  
Ferroelectric Phase Transition ◽  
Ferroelectric Phase ◽  
Electrocaloric Effect ◽  
Donor Doping ◽  
Temperature Window ◽  
Lower Temperature

The donor doping of Nb5+ for Ti4+ in the B sites of BaTiO3 rapidly shifts the ferroelectric phase transition to a lower temperature and diffuses it, so that the electrocaloric ΔTmax gradually reduces and the temperature window becomes much wider.

Lead Titanate is not a Classic Case of a Displacive Ferroelectric Phase Transition

1993 ◽  
Vol 32 (S2) ◽  
pp. 782 ◽  
Author(s):  
Bruce Ravel ◽  
Edward A. Stern ◽  
Yitzhak Yacobi ◽  
Fatih Dogan
Keyword(s):  
Phase Transition ◽  
Lead Titanate ◽  
Ferroelectric Phase Transition ◽  
Ferroelectric Phase ◽  
Classic Case

Ferroelectric phase transition in the whitlockite-type Ca9Fe(PO4)7; crystal structure of the paraelectric phase at 923 K

2004 ◽  
Vol 6 (2) ◽  
pp. 185-195 ◽  
Author(s):  
Bogdan I. Lazoryak ◽  
Vladimir A. Morozov ◽  
Alexei A. Belik ◽  
Sergey Yu. Stefanovich ◽  
Vadim V. Grebenev ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Phase Transition ◽  
Ferroelectric Phase Transition ◽  
Ferroelectric Phase ◽  
Paraelectric Phase

scholarly journals The influence of BaGeO3 on the properties of Ba(Ti1−xSx)O3 ceramics on the basis of sol-gel powders

2019 ◽  
Author(s):  
Roberto Köferstein
Keyword(s):  
Phase Transition ◽  
Ferroelectric Phase Transition ◽  
Ferroelectric Phase ◽  
Sintering Temperature ◽  
Sol Gel ◽  
Synthesis Method ◽  
Particle Sizes ◽  
Dielectric Measurements ◽  
Sintering Additive ◽  
Phase Transition Temperatures

Ba(Ti1−x−y SnxGey )O3 (BTSG-x-y; x = 0, 0.05; y = 0–0.05) powders were synthesized by a sol-gel (SG) method and for comparative purposes also by a mixed-oxide (MO) method. In this system, BaGeO3 functions as sintering additive. Due to smaller particle sizes of the SG powders a higher sintering activity was found, which resulted in reduced grain growth and in a more homogenous grain size distribution for the corresponding ceramics. The dependence on the paraelectric ⇆ ferroelectric phase transition, i.e. the phase transition temperature, thewidth of the transition region and completeness were examined by dielectric measurements,DTA as well as by SEM, EDX and XRD investigations with respect to the BaGeO3 content, synthesis method and sintering temperature. The phase transition temperatures of the SG ceramics are remarkably higher than those of the MO ceramics with the same nominal compositions. The reason is a lower tin concentration within the grains of SG ceramics as confirmed by EDX and XRD investigations. The presence of BaGeO3 in barium titanate–stannate system on the basis of a SG method caused an improved incorporation of tin in theBaTiO3 lattice.

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