Characterization of Epitaxial Bi-Layer-Structured Bi_5Ti_3FeO_(15) (m = 4) and Bi_4Ti_3O_(12)- Bi_5Ti_3FeO_(15) (m = 3-4) Natural-Superlattice-Structured Multiferroic Thin Films Prepared by Pulsed Laser deposition

摘要

Bi-layer-structured mutiferroic Bi_5Ti_3FeO_(15) (BTFO15) (m = 4) and natural-superlattice-structured Bi_4Ti_3O_(12)- Bi_5Ti_3FeO_(15) (BIT-BTFO15) (m = 3-4) thin films have been prepared on (001) and (110) oriented SrTiO_3 (STO) single crystal substrates by using pulsed laser deposition. X-ray diffraction patterns of these thin films on (001) STO single crystals shows the obtained thin films were (OOZ)-oriented layer-perovskite single phase, and BIT-BTFO15 (m = 3-4) natural-superlattice-structure has also been obtained. On (110) STO single crystal, layer perovskite (11l) oriented thin films have also been obtained. For characterizing ferroelectric properties, these thin films have been prepared on (001) and (110) oriented La-doped (3.73 wt%) STO single crystal substrates. From ferroelectric D-E hysteresis loops measurements, BTFO15 (m = 4) and BIT-BTFO (m = 3-4) thin films on (110) La-doped STO single crystals shows good ferroelectric hysteresis loops and their double remanent polarizations (2P_r) were 47 μC/cm~2 and 44 μC/cm~2, respectively. However, these thin films on (001) La-doped STO single crystals do not show ferroelectric characteristics.