[14a-A23-1~10] 6.1 Ferroelectric thin films

△ [14a-A23-7] Growth of orientation controlled epitaxial (Bi_, K)TiO₃ films by pulse laser deposition.

〇Yuichi Nemoto¹, Daichi Ichinose², Takao Shimizu³, Hiroshi Uchida⁴, Yusuke Sato⁵, Wakiko Yamaoka⁵, Hiroshi Funakubo^1,2,3 (1.Tokyo Tech. IGS, 2.Tokyo Tech. MCT, 3.Tokyo Tech. MECS, 4.Sophia Univ. FST, 5.TDK corp.)

Keywords:ferroelectric, lead free

The most popular material is Pb(Zr, Ti)O₃ that shows crystal symmetry change from tetragonal to rhombohedral across the boundaries, so called morphotropic phase boundary (MPB) that shows large piezoelectric coefficient together with relatively high Curie temeparature. However, these materials include toxic lead materials, so that the development of the lead-free materials is highly required. (Bi_1/2K_1/2)TiO₃ is known as a ferroelectric material with tetragonal symmetries. However, thin films of (Bi_1/2K_1/2)TiO₃ have been limited to solution-based methods, but the tetragonal symmetries of the deposited films have not been reported. Then, we succussed to prepare epitaxial (Bi, K)TiO₃ films with tetragonal symmetry for the first time and ferroelectric and piezoelectric properties were investigated. This time, We reported Growth of orientation controlled epitaxial (Bi_, K)TiO₃ films by pulse laser deposition.