X-ray study of phase transitions in efrroelectric Na0.5Bi0.5TiO3

Zvirgzds, Jānis; Kapostin, P. P.; Zvirgzde, J. V.; Kruzina, T. V.

doi:10.1080/00150198208210600

Cited by 270 publications

(137 citation statements)

References 6 publications

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“…The presence of superlattice spots in perovskite oxides indicate a doubling of the unit cell and it has been attributed to either cation ordering or oxygen octahedra tilting. 26,27 Since cation ordering is not likely to occur in these ceramics, [28][29][30] the electron diffraction results indicate that BNT-FE is rhombohedrally distorted, most likely with the R3c space group, [28][29][30] and BNT-AFE displays a pseudocubic perovskite structure with, at the moment, unknown octrahedra tilting. A mixed tilting system, either a combination of in-phase and antiphase tilting or a two phase mixture of one antiphase and one in-phase tilting, is possible.…”

Section: Resultsmentioning

confidence: 99%

“…31 It should be pointed out that the complexity and confusion in BNT-AFE trace their origin back to the base compound ͑Bi 1/2 Na 1/2 ͒TiO 3 . Earlier x-ray 28 and neutron 29 structural studies indicate that there are no antiparallel cation displacements in ͑Bi 1/2 Na 1/2 ͒TiO 3 , and the term "diffused antiferroelectric" was used to describe the mixed relaxor and antiferroelectric behavior. 29 Later, contradictory observations were reported in a detailed neutron diffraction study where antiparallel cation displacements were found in the antiferroelectric tetragonal phase.…”

Section: Discussionmentioning

confidence: 99%

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Effect of uniaxial stress on ferroelectric behavior of (Bi1/2Na1/2)TiO3-based lead-free piezoelectric ceramics

Tan

Aulbach

et al. 2009

Journal of Applied Physics

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Prior studies have shown that a field-induced ferroelectricity in ceramics with general chemical formula (1−x−y)(Bi1/2Na1/2)TiO3-xBaTiO3-y(K0.5Na0.5)NbO3 and a very low remanent strain can produce very large piezoelectric strains. Here we show that both the longitudinal and transverse strains gradually change with applied electric fields even during the transition from the nonferroelectric to the ferroelectric state, in contrast to known Pb-containing antiferroelectrics. Hence, the volume change and, in turn, the phase transition can be affected using uniaxial compressive stresses, and the effect on ferroelectricity can thus be assessed. It is found that the 0.94(Bi1/2Na1/2)TiO3-0.05BaTiO3-0.01(K0.5Na0.5)NbO3ceramic (largely ferroelectric), with a rhombohedral R3c symmetry, displays large ferroelectric domains, significant ferroelastic deformation, and large remanent electrical polarizations even at a 250 MPa compressive stress. In comparison, the 0.91(Bi1/2Na1/2)TiO3-0.07BaTiO3-0.02(K0.5Na0.5)NbO3ceramic (largely nonferroelectric) possesses characteristics of a relaxor ferroelectricceramic, including a pseudocubic structure, limited ferroelastic deformation, and low remanent polarization. The results are discussed with respect of the proposed antiferroelectric nature of the nonferroelectric state. Prior studies have shown that a field-induced ferroelectricity in ceramics with general chemical formula ͑1−x − y͒͑Bi 1/2 Na 1/2 ͒TiO 3 -xBaTiO 3 -y͑K 0.5 Na 0.5 ͒NbO 3 and a very low remanent strain can produce very large piezoelectric strains. Here we show that both the longitudinal and transverse strains gradually change with applied electric fields even during the transition from the nonferroelectric to the ferroelectric state, in contrast to known Pb-containing antiferroelectrics. Hence, the volume change and, in turn, the phase transition can be affected using uniaxial compressive stresses, and the effect on ferroelectricity can thus be assessed. It is found that the 0.94͑Bi 1/2 Na 1/2 ͒TiO 3 -0.05BaTiO 3 -0.01͑K 0.5 Na 0.5 ͒NbO 3 ceramic ͑largely ferroelectric͒, with a rhombohedral R3c symmetry, displays large ferroelectric domains, significant ferroelastic deformation, and large remanent electrical polarizations even at a 250 MPa compressive stress. In comparison, the 0.91͑Bi 1/2 Na 1/2 ͒TiO 3 -0.07BaTiO 3 -0.02͑K 0.5 Na 0.5 ͒NbO 3 ceramic ͑largely nonferroelectric͒ possesses characteristics of a relaxor ferroelectric ceramic, including a pseudocubic structure, limited ferroelastic deformation, and low remanent polarization. The results are discussed with respect of the proposed antiferroelectric nature of the nonferroelectric state.

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Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Effect of uniaxial stress on ferroelectric behavior of (Bi1/2Na1/2)TiO3-based lead-free piezoelectric ceramics

Tan

Aulbach

et al. 2009

Journal of Applied Physics

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“…Besides, high leakage currents and high coercive field (∼73 kV/cm) negatively affect the poling process and polarization saturation is difficult to achieve in conventionally fabricated BNT samples. In addition, BNT exhibits a low depolarization temperature ∼200 • C. Several workers [3][4][5][6][7][8][9][10][11][12][13][14][15][16] have investigated the electrical behavior, proposed more accurate measurement of the phase transition temperatures of BNT-based solid solutions, and determined their morphotropic phase boundary (MPB) compositions in order to improve dielectric and piezoelectric properties of BNT ceramic. Among these solid solutions, (Bi 0.5 Na 0.5 ) 1−x Ba x TiO 3 (BNBTx) has attracted an enormous global attention owing to the existence of a rhombohedraltetragonal morphotropic phase boundary (MPB) near x = 0.06 -0.08 in the system.…”

Section: Introductionmentioning

confidence: 99%

Electrical Properties and AC Conductivity of (Bi_0.5Na_0.5)_0.94Ba_0.06TiO₃ Ceramic

et al. 2012

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Lead-free perovskite (Bi 0.5 Na 0.5 ) 0.94 Ba 0.06 TiO 3 (BNBT06) was prepared by conventional ceramic fabrication technique at 1160 • C/3h in air atmosphere. The crystal structure, microstructure, dielectric, polarization, piezoelectric properties, and ac conductivity of the sample were studied. X-ray diffraction data confirmed the formation of a single phase tetragonal unit cell. Williamson-Hall plot was used to calculate the lattice strain and the apparent particle size. The experimental relative density of BNBT06 was found to be ∼96-97% of the theoretical one with an average grain size ∼4 μm. Room temperature dielectric constant and loss factor at 1 kHz were found to be equal to 781 and 0.085, respectively. Longitudinal piezoelectric charge coefficient of the poled sample under 2.5 kV/mm at 80 • C in silicone bath was found to be equal to 124 pC/N. Complex impedance and electric modulus spectroscopic analyses showed the dielectric relaxation in the material to be of non-Debye type. The Nyquist plots and conductivity studies showed the NTCR character of BNBT06. The correlated barrier hopping model (CBHM) as well as jump relaxation model (JRM) was found to successfully explain the mechanism of charge transport in BNBT06. The ac conductivity data were used to evaluate the minimum hopping length, apparent activation energy, and density of states at Fermi level.

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“…6 It is believed that NBT undergoes a phase transition sequence of high-temperature cubic ͑C͒ → paraelectric tetragonal ͑T͒ → FE rhombohedral ͑R͒ at temperatures of 520°C and 250°C, respectively. [7][8][9][10][11][12][13][14] The T phase is ferroelastic, and there is no characteristic dielectric anomaly at the C → T transition. 15,16 Controversy remains concerning the T → R transition.…”

Section: Introductionmentioning

confidence: 99%

Observation of partially incoherent ⟨110⟩ boundaries between polar nanodomains in Na1/2Bi1/2TiO3 single crystals

Yao

Yang

et al. 2010

Journal of Applied Physics

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The ferroelectric domain structure of Na 1/2 Bi 1/2 TiO 3 single crystals was investigated by transmission electron microscopy ͑TEM͒ and piezoforce microscopy ͑PFM͒. Bright-field TEM and PFM images revealed the presence of polar nanodomains, whose boundaries had a tendency to align along the ͗110͘. High resolution TEM images revealed planar defects along these ͗110͘ boundaries, which partially relaxed the coherency of the lattice.

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X-ray study of phase transitions in efrroelectric Na0.5Bi0.5TiO3

Cited by 270 publications

References 6 publications

Effect of uniaxial stress on ferroelectric behavior of (Bi1/2Na1/2)TiO3-based lead-free piezoelectric ceramics

Effect of uniaxial stress on ferroelectric behavior of (Bi1/2Na1/2)TiO3-based lead-free piezoelectric ceramics

Electrical Properties and AC Conductivity of (Bi_0.5Na_0.5)_0.94Ba_0.06TiO₃ Ceramic

Observation of partially incoherent ⟨110⟩ boundaries between polar nanodomains in Na1/2Bi1/2TiO3 single crystals

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X-ray study of phase transitions in efrroelectric Na0.5Bi0.5TiO3

Cited by 270 publications

References 6 publications

Effect of uniaxial stress on ferroelectric behavior of (Bi1/2Na1/2)TiO3-based lead-free piezoelectric ceramics

Effect of uniaxial stress on ferroelectric behavior of (Bi1/2Na1/2)TiO3-based lead-free piezoelectric ceramics

Electrical Properties and AC Conductivity of (Bi0.5Na0.5)0.94Ba0.06TiO3 Ceramic

Observation of partially incoherent ⟨110⟩ boundaries between polar nanodomains in Na1/2Bi1/2TiO3 single crystals

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Product

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Electrical Properties and AC Conductivity of (Bi_0.5Na_0.5)_0.94Ba_0.06TiO₃ Ceramic