[26a-E307-1~9] 9.1 Dielectrics, ferroelectrics

[26a-E307-8] Electrical and Electromechanical Properties of Bi_4-xLn_xTi₃O₁₂ Ceramics

〇Hiroshi Maiwa¹ (1.Shonan Inst. Tech.)

Keywords:Ferroelectrics, Bi4Ti3O12, Lead-free

Bi₄Ti₃O₁₂ (BIT) ceramics and Bi_3.25Ln_0.75Ti₃O₁₂ ceramics (Ln = La or Nd, BLT and BNT) ceramics were prepared by solid state reaction. The crystal structure, microstructure, and the dielectric and electromechanical properties are investigated. Substitution of Bi with La or Nd deteriorates sinterability, and the optimum sintering temperatures are higher than that of BIT. The firing temperatures of BIT, BLT, and BNT shown below are 1000 ℃, 1100 ℃ and 1150 ℃, respectively. In each case, the crystal grains grew as the sintering temperature increased. Most samples showed c-axis orientation in which flat particles spread. Figures 1 and 2 show polarization – electric field (P-E) loops and strain – electric field (s-E) loops of BIT, BLT and BNT, respectively. BNT has a large remanent polarization value, but also has a large coercive field (Ec). BLT shows the largest strain value among them. Since BNT has a large Ec, the maximum strain was not so large under the applied electric field. The results of piezoelectric properties will also be reported.