Structural aspects of the ferroelectric phase transition in lanthanum-substituted lead titanate

1995 ◽  
Vol 30 (1) ◽  
pp. 24-34 ◽  
Author(s):  
G. A. Rossetti ◽  
L. E. Cross ◽  
J. P. Cline
1993 ◽  
Vol 32 (S2) ◽  
pp. 782 ◽  
Author(s):  
Bruce Ravel ◽  
Edward A. Stern ◽  
Yitzhak Yacobi ◽  
Fatih Dogan

2015 ◽  
Vol 05 (02) ◽  
pp. 1550011
Author(s):  
Seonhyeop Shin ◽  
Jae-Hyeon Ko ◽  
Shinya Tsukada ◽  
Yukikuni Akishige ◽  
Krystian Roleder ◽  
...  

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.


1999 ◽  
Vol 227 (1) ◽  
pp. 189-192
Author(s):  
V. G. Gavrilyatchenko ◽  
V. D. Komarov ◽  
A. Leyderman ◽  
E. G. Fesenko

2007 ◽  
Vol 75 (22) ◽  
Author(s):  
N. Jaouen ◽  
A. C. Dhaussy ◽  
J. P. Itié ◽  
A. Rogalev ◽  
S. Marinel ◽  
...  

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Đorđe Dangić ◽  
Olle Hellman ◽  
Stephen Fahy ◽  
Ivana Savić

AbstractThe proximity to structural phase transitions in IV-VI thermoelectric materials is one of the main reasons for their large phonon anharmonicity and intrinsically low lattice thermal conductivity κ. However, the κ of GeTe increases at the ferroelectric phase transition near 700 K. Using first-principles calculations with the temperature dependent effective potential method, we show that this rise in κ is the consequence of negative thermal expansion in the rhombohedral phase and increase in the phonon lifetimes in the high-symmetry phase. Strong anharmonicity near the phase transition induces non-Lorentzian shapes of the phonon power spectra. To account for these effects, we implement a method of calculating κ based on the Green-Kubo approach and find that the Boltzmann transport equation underestimates κ near the phase transition. Our findings elucidate the influence of structural phase transitions on κ and provide guidance for design of better thermoelectric materials.


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