Synthesis and characteristics of nature-superlattice-structured Bi3TiNbO9–Bi4Ti3O12 ferroelectric thin films by MOD

✍ Scribed by Hua Wang; Minfang Ren; Masanori Okuyama

• Publisher: Elsevier Science
• Year: 2007
• Tongue: English
• Weight: 625 KB
• Volume: 136
• Category: Article
• ISSN: 0921-5107
• DOI: 10.1016/j.mseb.2006.04.047

✦ Synopsis

Natural-superlattice-structured ferroelectric thin films, Bi 3 TiNbO 9 -Bi 4 Ti 3 O 12 (BTN-BIT), have been synthesized on Pt/Ti/SiO 2 /Si by metal organic decomposition (MOD) using BTN-BIT (1 mol:1 mol) solution. BTN-BIT films show natural-superlattice peaks below 2θ = 20 • in X-ray diffraction patterns, which indicate that the BTN-BIT films annealed at 700-800 • C in O 2 ambient are consisted of iteration of two unit cells of Bi 3 TiNbO 9 and one unit cell of Bi 4 Ti 3 O 12 . As the annealing temperature increases from 600 to 750 • C, uniform and crack-free films, better crystallinity and ferroelectric properties can be obtained, but the pyrochlore phase in BTN-BIT films annealed over 800 • C would impair the ferroelectric properties. With the increase of O 2 flow rate from 0.5 to 1.5 L/min, both remanent polarization P r and coercive electric field E C increase, which are mainly attributed to reduction of the vacanvies of Bi and oxide ions in the films. Natural-superlattice-structured BTN-BIT thin films having 2-1 superlattice annealed at 750 • C in O 2 ambient with a flow rate of 1.5 L/min exhibit superior ferroelectric properties of P r = 23.5 C/cm 2 and E C = 135 kV/cm.