Relaxor-normal ferroelectric phase transition and significantly enhanced electromechanical strain behavior in Bi(Ni1/2Ti1/2)O3–PbTiO3–Pb(Mg1/3Nb2/3)O3 ternary system close to the morphotropic phase boundary

2015 ◽  
Vol 35 (13) ◽  
pp. 3485-3493 ◽  
Author(s):  
Donggeng Zheng ◽  
Ruzhong Zuo
Keyword(s):  
Phase Transition ◽  
Ternary System ◽  
Phase Boundary ◽  
Morphotropic Phase Boundary ◽  
Ferroelectric Phase Transition ◽  
Ferroelectric Phase ◽  
Strain Behavior

Dielectric Behavior of Mn-doped Morphotropic Phase Boundary Composition in the Pb(Zn1/3Nb2/3)O3–BaTiO3– PbTiO3 System

2002 ◽  
Vol 17 (5) ◽  
pp. 1192-1198 ◽  
Author(s):  
W. Z. Zhu ◽  
M. Yan ◽  
A. L. Kholkin ◽  
P. Q. Mantas ◽  
J. L. Baptista
Keyword(s):  
Phase Transition ◽  
Dielectric Permittivity ◽  
Phase Boundary ◽  
Morphotropic Phase Boundary ◽  
Ferroelectric Phase ◽  
Frequency Dispersion ◽  
Rhombohedral Phase ◽  
Progressive Increase ◽  
Dielectric Behavior ◽  
Underlying Mechanisms

The dielectric behavior of manganese-doped morphotropic phase boundary (MPB) composition in the Pb(Zn1/3Nb2/3)O3–BaTiO3–PbTiO3 (PZN–BT–PT) system is described in this paper. Materials with perovskite structure were fabricated using the precursor approach. Addition of Mn stabilized the rhombohedral phase against the tetragonal one, moving the MPB territory toward the PbTiO3-rich side. Both the dielectric permittivity maximum (∈′m) and phase transition temperature (Tmax) were reduced by increasing Mn2+ content. Frequency-dispersion characteristics of Tmax were weakened while the frequency spectrum of the dielectric permittivity (∈′) was broadened, reflecting different underlying mechanisms. The broadness of paraelectric to ferroelectric phase transition was significantly enhanced by Mn-doping. This was associated with progressive increase in the degree of chemical heterogeneity on B-site cations. The observed proximity of the non-Curie–Weiss region to Tmax as well as shrinkage of this region for doped compositions suggest increased stability of the ferroelectric phase.

scholarly journals The origin of the lattice thermal conductivity enhancement at the ferroelectric phase transition in GeTe

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Đorđe Dangić ◽  
Olle Hellman ◽  
Stephen Fahy ◽  
Ivana Savić
Keyword(s):  
Phase Transition ◽  
Thermal Conductivity ◽  
Phase Transitions ◽  
Thermoelectric Materials ◽  
Ferroelectric Phase Transition ◽  
Lattice Thermal Conductivity ◽  
Ferroelectric Phase ◽  
Structural Phase ◽  
High Symmetry ◽  
Structural Phase Transitions

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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