Studies of Diffuse Phase Transition in Ferroelectric Solid Solution Pb1-xK2xNb2O6(x = 0.1, 0.2, 0.25 and 0.3)

Belboukhari, A.; Abkhar, Z.; Choukri, E.; Gagou, Y.; Abdelmoula, N.; Elmoznine, R.; Mezzane, D.; Khemakhem, H.; Marssi, M. El; Razumnaya, A. G.; Raevski, I. P.; Luk’yanchuk, I.

doi:10.1080/00150193.2013.786619

Cited by 11 publications

(5 citation statements)

References 18 publications

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“…But up until now, the thermal expansion properties of TTB materials have not been well studied. [18][19][20] Among the TTB oxides, lead potassium niobate Pb 2 KNb 5 -O 15 (PKN) is one of the best-known compounds, [21][22][23][24][25][26][27][28][29][30] and was first synthesized by E. C. Subbarao as a solid solution of PbNb 2 O 6 in 1960. 21 The piezoelectric, ferroelectric-ferroelastic coupling, optical properties, and surface-acoustic-wave (SAW) characteristics have been studied previously.…”

Section: Introductionmentioning

confidence: 99%

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Structure and thermal expansion of the tungsten bronze Pb₂KNb₅O₁₅

Lin

Wang

et al. 2014

Dalton Trans.

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The structure and thermal expansion behavior of the tetragonal tungsten bronze oxide Pb2KNb5O15 were investigated by neutron powder diffraction and high-temperature X-ray diffraction. Below the Curie temperature, T(C) (orthorhombic phase, T(C) ≈ 460 °C), the cell parameters a and c increase with temperature, while b decreases. The thermal expansion coefficients are α(a) = 1.29 × 10(-5) °C(-1), α(b) = -1.56 × 10(-5) °C(-1), and α(c) = 1.62 × 10(-5) °C(-1). Temperature-dependent second harmonic generation (SHG), dielectric, and polarization-electrical field (P-E) hysteresis loop measurements were performed to study the symmetry and electric properties. We show that the distortion and cooperative rotation of NbO6 octahedrons are directly responsible for the negative thermal expansion coefficient along the polar b axis. It is suggested that Pb-O covalency, especially in the large and asymmetric pentagonal prisms, may be related to orthorhombic distortion and abnormal spontaneous polarization along the b axis. This study shows that tungsten bronze families are possible candidates for exploring negative thermal expansion materials.

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Section: Introductionmentioning

confidence: 99%

“…21 The piezoelectric, ferroelectric-ferroelastic coupling, optical properties, and surface-acoustic-wave (SAW) characteristics have been studied previously. [21][22][23][24][25][26][27][28][29][30] PKN has a high Curie Temperature: T C ≈ 460 °C. 22,31 Above T C , the unit cell of PKN is tetragonal with space group P4/mbm (no.…”

Section: Introductionmentioning

confidence: 99%

Structure and thermal expansion of the tungsten bronze Pb₂KNb₅O₁₅

Lin

Wang

et al. 2014

Dalton Trans.

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“…Among the TTB ferroelectrics, Pb-based niobates have high Curie temperatures ( T C ) and well electric properties. , Lead potassium niobate (Pb 2 KNb 5 O 15 , PKN for short; T C = 460 °C) is a good example with well ferroelectric, dielectric, and optical properties. − Both the structural and ferroelectric aspects have been widely studied. − , In our previous study, we reported the abnormal thermal expansion behavior in PKN. Below the Curie temperature, the lattice constant b (polar axis) decreases abnormally with an increase of the temperature.…”

Section: Introductionmentioning

confidence: 99%

“…9−11 Both the structural and ferroelectric aspects have been widely studied. [9][10][11]13 In our previous study, 14 we reported the abnormal thermal expansion behavior in PKN. Below the Curie temperature, the lattice constant b (polar axis) decreases abnormally with an increase of the temperature.…”

Section: ■ Introductionmentioning

confidence: 99%

Ordered Structure and Thermal Expansion in Tungsten Bronze Pb₂K_0.5Li_0.5Nb₅O₁₅

Lin

Rong²,

et al. 2014

Inorg. Chem.

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The crystal structure and thermal expansion behaviors of a new tetragonal tungsten bronze (TTB) ferroelectric, Pb2K(0.5)Li(0.5)Nb5O15, were systematically investigated by selected-area electron diffraction (SAED), neutron powder diffraction, synchrotron X-ray diffraction (XRD), and high-temperature XRD. SAED and Rietveld refinement reveal that Pb2K(0.5)Li(0.5)Nb5O15 displays a commensurate superstructure of simple orthorhombic TTB structure at room temperature. The structure can be described with space group Bb2₁m. The transition to a paraelectric phase (P4/mbm) occurs at 500 °C. Compared with Pb2KNb5O15 (PKN), the substitution of 0.5K(+) with small 0.5Li(+) into PKN causes the tilting of NbO6 octahedra away from the c axis with Δθ ≈ 10° and raises the Curie temperature by 40 °C, and the negative thermal expansion coefficient along the polar b axis increases more than 50% in the temperature range 25-500 °C. We present that, by introduction of Li(+), the enhanced spontaneous polarization is responsible for the enhanced negative thermal expansion along the b axis, which may be caused by more Pb(2+) in the pentagonal caves.

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“…The parameters c for BNNW025 are found close to 1.45-1.95, which leads to the conclusion that DPT in BNNW025 is of ''incomplete'' nature. This behavior is often observed in TTB ceramics, whose explanation is related to the movement of domain walls in ferroelectric materials [6,14].…”

Section: Diffusive Nature Of Ferroelectric Transitionmentioning

confidence: 85%

Diffuse phase transition and impedance spectroscopy analysis of Ba2.15−x Na0.7+x Nb5−x W x O15 (x = 0.25) ferroelectric ceramic

Neqali

Belboukhari²,

Bensaid³

et al. 2016

Appl. Phys. A

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A new rare earth ferroelectric tetragonal tungsten bronze compound with general formula Ba 2.15-xNa 0.7?x Nb 5-x W x O 15 (x = 0.25) was elaborated as ceramic and investigated using X-ray diffraction and dielectric measurements. The results show a tetragonal phase with the space group P4bm. Special emphasis was done to characterize diffuse phase transition (DPT) that occurs close to 472°C. Using dielectric measurements in a frequency range of (10 Hz-1 MHz) and in a temperature range (25-550°C), we have shown that the real part of the permittivity close to DPT is well described by Santos-Eiras phenomenological model. Space charge polarization, relaxation phenomena and free charges conductivity have been analyzed using dielectric, impedance spectroscopy and Nyquist plots showed non-Debye (polydispersive) type relaxation. In paraelectric phase, the Arrhenius activation energies were determined. Frequency dependence of ac conductivity at different temperatures follows the Jonscher's universal law (Jonscher et al. in J Mater Sci 20:4431, 1985).

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Studies of Diffuse Phase Transition in Ferroelectric Solid Solution Pb_1-xK_2xNb₂O₆(x = 0.1, 0.2, 0.25 and 0.3)

Cited by 11 publications

References 18 publications

Structure and thermal expansion of the tungsten bronze Pb₂KNb₅O₁₅

Structure and thermal expansion of the tungsten bronze Pb₂KNb₅O₁₅

Ordered Structure and Thermal Expansion in Tungsten Bronze Pb₂K_0.5Li_0.5Nb₅O₁₅

Diffuse phase transition and impedance spectroscopy analysis of Ba2.15−x Na0.7+x Nb5−x W x O15 (x = 0.25) ferroelectric ceramic

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Studies of Diffuse Phase Transition in Ferroelectric Solid Solution Pb1-xK2xNb2O6(x = 0.1, 0.2, 0.25 and 0.3)

Cited by 11 publications

References 18 publications

Structure and thermal expansion of the tungsten bronze Pb2KNb5O15

Structure and thermal expansion of the tungsten bronze Pb2KNb5O15

Ordered Structure and Thermal Expansion in Tungsten Bronze Pb2K0.5Li0.5Nb5O15

Diffuse phase transition and impedance spectroscopy analysis of Ba2.15−x Na0.7+x Nb5−x W x O15 (x = 0.25) ferroelectric ceramic

Contact Info

Product

Resources

About

Studies of Diffuse Phase Transition in Ferroelectric Solid Solution Pb_1-xK_2xNb₂O₆(x = 0.1, 0.2, 0.25 and 0.3)

Structure and thermal expansion of the tungsten bronze Pb₂KNb₅O₁₅

Structure and thermal expansion of the tungsten bronze Pb₂KNb₅O₁₅

Ordered Structure and Thermal Expansion in Tungsten Bronze Pb₂K_0.5Li_0.5Nb₅O₁₅