Textured Sr0.53Ba0.47Nb2O6 ceramics with a relative density of >95% were fabricated using templated grain growth (TGG). Acicular KSr2Nb5O15 template particles synthesized via a molten salt process were aligned by tape casting in a mixture of solid-state-synthesized SrNb2O6 and BaNb2O6 powders. The resulting ceramics possessed strong fiber texture along the polar axis ([001]) of the strontium barium niobate. Samples with 15.4 wt% templates attained a textured fraction of 0.82 after sintering at a temperature of 1450°C for 4 h. These materials showed peak dielectric constants of 7550 at 1 kHz, remanent polarizations of 13.2 μC/cm2, saturation polarizations of 21 μC/cm2 (60%–85% of the single-crystal value), piezoelectric strain coefficients of 78 pC/N (70%–85% of the single-crystal value), and room-temperature pyroelectric coefficients of 2.9 × 10−2μC·(cm2·°C)−1 (52% of the single-crystal value). These results show that TGG is a viable option for accessing single-crystal properties in polycrystalline ceramics.

Fabrication and Electrical Properties of Textured Sr0.53Ba0.47Nb2O6 Ceramics by Templated Grain Growth

Fiber textured Sr0.53Ba0.47Nb2O6 ceramics were reactively sintered to ≥95% of the theoretical density from a mixture of SrNb2O6 and BaNb2O6 powders. Texture in 〈001〉 was obtained by templated grain growth on 〈001〉-oriented acicular KSr2Nb5O15 template particles. The most highly textured ceramics had a peak dielectric constant of 23,600 (at Tc = 128 °C), a remanent polarization (Pr) of 20.3 µC/cm2, a saturation polarization (Psat) of 24 µC/cm2 (69–96% of single crystal), and a piezoelectric charge coefficient (d33) of 84 pC/N (76–93% of single crystal). A model, correlating polarization with grain orientation, predicts that Pr increases sharply when a percolating grain network forms to transfer charge between elongated grains.

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Dielectric and piezoelectric properties of textured Sr0.53Ba0.47Nb2O6 ceramics prepared by templated grain growth

Barium Sodium Niobate (BNN) belongs to tungsten bronze type Ferroelectric material The non linear coefficients of BNN are twice that of LiNbO3 Large single crystal of BNN is useful in frequency doubling applications because its conversion efficiency and resistance to optical damage are superior to LiNbO3 Present review describes the preparative details, sturcture, ferroelectric and electro optic properties of BNN

Review: Review of electrooptic and ferroelectric properties of barium sodium niobate single crystals

Structural and dielectric properties of Ba4R2Ti4Nb6O30 (R=Y, Sm and Dy) ferroelectric ceramics

Polycrystalline samples of Ba5RTi3Nb7O30 [R=Nd, Eu, Gd], were prepared using high-temperature solid-state reaction technique. Preliminary X-ray structural analysis of the compounds shows the formation of single phase compounds (orthorhombic crystal system) at room temperature. Detailed studies of dielectric properties (ɛ, tanδ,σ) as a function of frequency (400 Hz to 10 kHz) and temperature (30° to 380°C) show that these compounds exhibit diffuse ferroelectric phase transition.

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Ferroelectric phase transition in Ba5RTi3Nb7O30 [R=Nd, Eu, Gd] ceramics

Influence du dopage sur la constante de Curie, la constante dielectrique et la temperature de Curie

Effect of rare-earth ions on the properties of modified (SrBa)Nb2O6 ceramics

Orthorhombic tungston bronze type ferroelectric barium sodium niobate (BNN) has been found to be an outstanding non-linear optical material and is particularly useful for the second harmonic generation. Van Uitert et al. [1] has studied d.c. resistivity in BNN single crystal and estimated activation energies in the temperature ranges 480 to 700 K and 770 to 900 K which cover the Curie temperature of the material) to be 1.00 and 1.33 eV, respectively. Further, resistivity is decreased with increasing temperature in the range 480 to 900 K showing negative temperature coefficient effect in BNN, and a maximum resistivity of the order of 10 l° l)cm was obtained. In this letter d.c. resistivity studies on rare-earth lanthanum-doped barium sodium niobate are reported for the first time.

K. Sambasiva Rao

Papers

Effect of rare-earth ions on the properties of modified (SrBa)Nb2O6 ceramics

Anomalous electrical behaviour of barium sodium niobate ceramics doped with trivalent lanthanum

Dielectric behaviour of modified ferroelectric Ba4Na2Nb10O30 ceramics

Diffuse phase transition of lithium zirconium bearing barium titanate

Dielectric and resistivity properties of lanthanum doped Ba(Cu1/3Ta2/3)O3 and Ba(Cu1/3Nb2/3)O3