New Ferroelectric BaTi₂O₅

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

“…It is well known that BT 2 crystal may easily grow along the bdirection from the melt and needle-like BT 2 crystals were often prepared. 8,10) Although no report on the abnormal grain growth during the sintering of BT 2 , the elongated direction might be the b-axis of BT 2 . Many gaps at the grain boundaries might be formed by significant difference of the linear thermal expansion () among a-, b-and c-directions of BT 2 ( a ¼ 5:14, b ¼ 0:86 and c ¼ 12:5 Â 10 À6 K À1 at 900 K 10) ).…”

“…9) It is known that needle-like single-crystalline BT 2 would precipitate from melts, where the growth direction is parallel to b-axis. 8) This suggests that the b-axis oriented poly-crystalline BT 2 can be prepared by a melt-solidification process. In the present study, an arc-melting method was applied to prepare the b-axis oriented poly-crystalline BT 2 , and the dielectric properties were compared with those of non-oriented polyand single-crystalline BT 2 .…”

“…[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]. Polycrystalline BaTi 2 O 5 ceramic was prepared by laser rapid solidification method [22].…”