scispace - formally typeset
Search or ask a question
Journal ArticleDOI

Dielectric, ferroelectric, and piezoelectric properties of (Na0.47Bi0.47Ba0.06)1−xSrxTiO3 lead-free ceramics with different mean radii of the A-site cations

01 Oct 2019-Journal of Materials Science: Materials in Electronics (Springer US)-Vol. 30, Iss: 20, pp 18539-18547
TL;DR: In this paper, the effects of Sr2+-doping on microstructure, ferroelectric, impedance, dielectric, and piezoelectric properties of the ceramics were investigated.
Abstract: The ceramics (Na0.47Bi0.47Ba0.06)1−xSrxTiO3 were prepared by means of a solid-state sintering method. Effects of Sr2+-doping on microstructure, ferroelectric, impedance, dielectric, and piezoelectric properties of the ceramics were investigated. Variation of electrical properties of the ceramics with the change of the mean radii of the A-site cations was shown. All ceramics exhibit dense microstructures and pure perovskite structure. Dielectric behavior is related to the electric poling and Sr2+ amount. Compared to the ceramic with x = 0, the values of coercive field of the ceramics with x = 0.03 and 0.05 decrease from 34.7 to 27.6 kV/cm and 20.4 kV/cm, respectively; the corresponding remnant polarization values increase from 28.5 to 32.8 μC/cm2 and 31.2 μC/cm2, respectively. The ceramics with x = 0, 0.01, 0.02, 0.03, 0.05, and 0.08 exhibit the piezoelectric constant (d33) values of 119, 123, 138, 169, 187, and 91 pC/N, respectively. With the increase of annealing temperature, the samples with x = 0.01, 0.02, and 0.03 show good temperature stability of d33.
Citations
More filters
Journal ArticleDOI
TL;DR: In this paper, the authors used BaTiO3 nanowires to replace the traditional TiO3 solution in off-MPB 0.88(Na 0.5Bi0.5)-0.06-0.

9 citations

Journal ArticleDOI
TL;DR: In this article, the authors showed that co-doping of Bi3+ and Fe3+ ions from 0% to 80% leads to a decrease of the direct band gap energy from 3.29 to 1.91 eV, and a shift of the band gap edges, namely the conduction band minimum and valence band maximum.

6 citations

Journal ArticleDOI
TL;DR: In this article, the dielectric properties of lead-free ferroelectric ceramics (Bi0.5Na0.94Ba0.06Ti1−xAlxO3−δ) obtained via a solid-state reaction method were studied.
Abstract: Microstructure and dielectric properties of the lead-free ferroelectric ceramics (Bi0.5Na0.5)0.94Ba0.06Ti1−xAlxO3−δ (abbreviated as BNBTA/x, x = 0, 0.04, 0.06, 0.08) obtained via a solid-state reaction method were studied. The ceramics with x≤0.06 exhibit pure structure without detectable secondary phase by X-ray diffraction measurement. There appears a second phase in the ceramic BNBTA/0.08. With an increase in the Al3+ amount, dielectric constant of the ceramics decreases, and the change in dielectric constant with increasing temperature between the two dielectric characteristic temperatures (TRE and Tm) is gradual. The poled ceramic BNBTA/0 shows a steep increase in permittivity at the temperature denoted as Td around 100 °C. But, the poled ceramics with x > 0 do not exhibit the Td anomaly on the permittivity spectra. The diffuse dielectric behavior around Tm was studied via the Curie–Weiss law and modified Curie–Weiss law. Compared to the ceramic BNBTA/0, the Al3+ -doped ceramics show slim ferroelectric hysteresis loops. The temperature-dependent ferroelectric properties and energy-storage behavior were studied.

4 citations

References
More filters
Journal ArticleDOI
TL;DR: The effective ionic radii of Shannon & Prewitt [Acta Cryst. (1969), B25, 925-945] are revised to include more unusual oxidation states and coordinations as mentioned in this paper.
Abstract: The effective ionic radii of Shannon & Prewitt [Acta Cryst. (1969), B25, 925-945] are revised to include more unusual oxidation states and coordinations. Revisions are based on new structural data, empirical bond strength-bond length relationships, and plots of (1) radii vs volume, (2) radii vs coordination number, and (3) radii vs oxidation state. Factors which affect radii additivity are polyhedral distortion, partial occupancy of cation sites, covalence, and metallic character. Mean Nb5+-O and Mo6+-O octahedral distances are linearly dependent on distortion. A decrease in cation occupancy increases mean Li+-O, Na+-O, and Ag+-O distances in a predictable manner. Covalence strongly shortens Fe2+-X, Co2+-X, Ni2+-X, Mn2+-X, Cu+-X, Ag+-X, and M-H- bonds as the electronegativity of X or M decreases. Smaller effects are seen for Zn2+-X, Cd2+-X, In2+-X, pb2+-X, and TI+-X. Bonds with delocalized electrons and therefore metallic character, e.g. Sm-S, V-S, and Re-O, are significantly shorter than similar bonds with localized electrons.

51,997 citations

Journal ArticleDOI
TL;DR: In this paper, general guidelines for the development of lead-free piezoelectric ceramics are presented, ranging from atom to phase diagram, and the current development stage in lead free piezoceramics is then critically assessed.
Abstract: A large body of work has been reported in the last 5 years on the development of lead-free piezoceramics in the quest to replace lead–zirconate–titanate (PZT) as the main material for electromechanical devices such as actuators, sensors, and transducers. In specific but narrow application ranges the new materials appear adequate, but are not yet suited to replace PZT on a broader basis. In this paper, general guidelines for the development of lead-free piezoelectric ceramics are presented. Suitable chemical elements are selected first on the basis of cost and toxicity as well as ionic polarizability. Different crystal structures with these elements are then considered based on simple concepts, and a variety of phase diagrams are described with attractive morphotropic phase boundaries, yielding good piezoelectric properties. Finally, lessons from density functional theory are reviewed and used to adjust our understanding based on the simpler concepts. Equipped with these guidelines ranging from atom to phase diagram, the current development stage in lead-free piezoceramics is then critically assessed.

2,510 citations

Journal ArticleDOI
TL;DR: In this paper, the authors used impedance spectroscopy for unravelling the complexities of such materials, which functions by utilizing the different frequency dependences of the constituent components for their separation, and showed that electrical inhomogeneities in ceramic electrolytes, electrode/electrolyte interfaces, surface layers on glasses, ferroelectricity, positive temperature coefficient of resistance behavior and even ferrimagnetism can all be probed, successfully.
Abstract: Electroceramics are advanced materials whose properties and applications depend on the close control of structure, composition, ceramic texture, dopants and dopant (or defect) distribution. Impedance spectroscopy is a powerful technique for unravelling the complexities of such materials, which functions by utilizing the different frequency dependences of the constituent components for their separation. Thus, electrical inhomogeneities in ceramic electrolytes, electrode/electrolyte interfaces, surface layers on glasses, ferroelectricity, positive temperature coefficient of resistance behavior and even ferrimagnetism can all be probed, successfully, using this technique.

2,004 citations

Journal ArticleDOI
TL;DR: In this paper, a rhombohedral (Fα)-tetragonal (Fβ) morphotropic phase boundary (MPB) is shown to exist at x=0.06~0.07 by X-ray data, and dielectric and piezoelectric properties are investigated.
Abstract: One of the (Bi1/2Na1/2)TiO3 (BNT)-based solid solutions, Ba-modified bismuth sodium titanate, (Bi1/2Na1/2)1-xBaxTiO3 (BNBT), is studied for its dielectric and piezoelectric properties as a new group of lead-free piezoelectric ceramics. A rhombohedral (Fα)-tetragonal (Fβ) morphotropic phase boundary (MPB) is shown to exist at x=0.06~0.07 by X-ray data, and dielectric and piezoelectric properties. BNBT ceramics with the MPB composition are superior as piezoelectric ceramics in high-frequency ultrasonic applications or as piezoelectric actuator materials because of a lower free permittivity, e33T/e0, and a high electromechanical coupling factor, kt or k33, along with high mechanical strength.

1,897 citations

Journal ArticleDOI
TL;DR: In this paper, the critical exponent γ in the relation between the dielectric constant and temperature (1/e − 1/em = C'-1x (T −Tm)γ) has been determined precisely for relaxor ferroelectrlics Pb(Mg1/3Nb2/3)O3, and a related solid solution 0.88Pb (Zn 1/3 Nb 2/3)-O3-0. I2PbT103.
Abstract: The critical exponent γ in the relation between the dielectric constant and temperature (1/e—1/em = C'-1x (T—Tm)γ) has been determined precisely for relaxor ferroelectrlics Pb(Mg1/3Nb2/3)O3, Pb(Zn1/3 Nb2/3)O3 and a related solid solution 0.88Pb (Zn1/3 Nb2/3)O3-0. I2PbT103, as well as for normal ferroelectrics BaTiO3 and K(Ta0. 55Nb0.45)O3. A high correlation of the γ value with the plase transition diffuseness has been found empirically. Moreover, this γ value is very close to another critical exponent γ* which is defined in the relation between the dielectric constant and hydrostatic pressure (1/e—1/em = C* (p—pm)γ*)

1,102 citations