Dielectric Property of Single Crystalline BaTi<SUB>2</SUB>O<SUB>5</SUB> Prepared by a Floating Zone Method

Abstract

Single crystalline BaTi 2 O 5 was prepared by a floating zone method. The permittivity of single crystalline BaTi 2 O 5 perpendicular to a (010) plane showed the maximum value of 20500 at 748 K obeying the Curie-Weiss law at higher temperatures. The permittivity perpendicular to (100) and (001) planes were 140 and 70, respectively almost independent of temperature. A transition temperature measured by a dilatometer was in agreement with a Curie temperature. The relationship between polarization and electrical field perpendicular to the (010) plane showed ferroelectric hysteresis. No hysteresis was observed in the direction perpendicular to (100) and (001) planes. The electrical conductivity perpendicular to the (010) was larger than those of (100) and (001) planes. The activation energy of electrical conductivity was 147 to 180 kJ mol À1 independent of directions.

Dielectric Properties of Poly- and Single-Crystalline BaTi<SUB>2</SUB>O<SUB>5</SUB>

“…A floating zone (FZ) method was used to prepare singlecrystalline BT 2 whose surface were cut parallel to (001) and (010) planes 6) in size of 2 Â 2 Â 0:3 mm. The crystal phase was identified by X-ray diffraction (XRD).…”

“…[1][2][3][4][5] Our group 6,7) and Akishige et al 8) independently synthesized single-crystalline BT 2 and reported the significant ferroelectricity only in the bdirection. Since BT 2 can be easily decomposed into BaTiO 3 (BT) and Ba 6 Ti 17 O 40 (B 6 T 17 ) above 1500 K, large-scale crystalline BT 2 can be hardly prepared.…”

Nanocrystalline BaTi2O5 dielectric ceramic prepared by full crystallization from containerless solidified glass

“…BaTi 2 O 5 has been discovered as a new ferroelectric compound by Akashi et al [19,20] and Akishige et al [21]. The single-crystalline BaTi 2 O 5 prepared by floating zone melting shows a high Curie temperature (T C = 430-475 ℃) and a high permittivity in b-direction without lead additives [19,20].…”

“…The single-crystalline BaTi 2 O 5 prepared by floating zone melting shows a high Curie temperature (T C = 430-475 ℃) and a high permittivity in b-direction without lead additives [19,20]. Hence, BaTi 2 O 5 ceramic is fabricated and studied as a promising environmentally friendly material [15,[21][22][23][24].…”

Nanocomposite ceramics based on La-doped BaTi2O5 and BaTiO3 with high temperature-independent permittivity and low dielectric loss

“…A new high temperature ferroelectric barium titanate, BaTi 2 O 5 , was discovered recently in Japan [1][2][3][4]. The permittivity of single crystals is very anisotropic with values of ∼20,000 in the direction of the polar b axis of the monoclinic cell, but much smaller values of ∼100 in directions perpendicular to the polar axis; the Curie temperature, T c , is ∼430°C.…”