2017年第78回応用物理学会秋季学術講演会

講演情報

一般セッション(口頭講演)

9 応用物性 » 9.1 誘電材料・誘電体

[6a-A502-1~14] 9.1 誘電材料・誘電体

2017年9月6日(水) 09:00 〜 12:45 A502 (502)

永田 肇(東理大)、和田 智志(山梨大)、上野 慎太郎(山梨大)

11:30 〜 11:45

[6a-A502-10] The role of the heat treatment on enhancement of electrical properties in BiFeO3-BaTiO3 lead-free system

〇(DC)Sangwook Kim1、Gopal Prasad Khanal1、Sintaro Ueno1、Chikako Moriyoshi2、Yoshihiro Kuroiwa2、Satoshi Wada1 (1.University of Yamanashi、2.Hiroshima University)

キーワード:BiFeO3-BaTiO3, Heat treatment

The lead-based piezoelectric materials, such as Pb(Zr,Ti)O3, are widely used in the piezoelectric devices, because of their high piezoelectric properties in morphotropic phase boundary. However, high toxicity and environmental problem of lead, the lead has been restricted for use. Recently, BiFeO3-BaTiO3 lead-free system is one of replacement for lead-based piezoelectric materials, because their high Curie temperature. In the early stage of BiFeO3-BaTiO3 study, the electrical properties of BiFeO3-BaTiO3 were less than those of other piezoelectric materials, because of high conductivity of BiFeO3. Recently, it is reported that electrical properties were enhanced with heat treatment process in BiFeO3 ceramics.
In this study, 0.80BiFeO3-0.20BaTiO3 (BF20BT) lead-free ceramics were fabricated with solid state reaction method. In order to study for thermal treatment effects, the three types samples were prepared with as-sintering (BF20BTS), annealing (BF20BTA), and quenching (BF20BTQ) process. The crystal structure were investigated from x-ray diffractometer and Rietveld method. The crystal structure were observed with rhombohedral structure. The lattice parameter, volume, and lattice distortion were increased with quenching process. The piezoelectric properties were investigated from strain – electric field (S-E) curves. The piezoelectric properties were increased with quenching process. The ferroelectric properties were observed with polarization – electric field (P-E) hysteresis loops. The remanent polarization were increased with quenching process. The imprint behaviors was observed in BF20BTS and BF20BTA. However, the imprint behaviors was not observed in the BF20BTQ ceramics. In other study for quenching effect, the bond-length and polyhedral distortion were calculated with final structure refinement results. The A-O bond length and B-O bond length behaviors were diffraction exhibited with thermal treatment process. More detailed structural and electrical properties will be discussed in presentation.