title: Synthesis and characterization of self-assembled c-axis oriented Bi2Sr3Co2O(y) thin films by the sol-gel method.
abstract: Bi(2)Sr(3)Co(2)O(y) thin films are prepared on SrTiO(3) (100), (110) and (111) single crystal substrates using the sol-gel method. All the thin films are c-axis oriented regardless of the orientation of the substrate suggesting self-assembled c-axis orientation, and X-ray photoelectron spectroscopy results give evidence of coexistence of Co(3+) and Co(2+) ions in the derived films. Transmission electronic microscopy observations reveal that all samples are c-axis oriented with no obvious differences for different samples, and the c-axis lattice constant is determined as ~15 Å suggesting the misfit structure. A phenomenological thermodynamic phase diagram for self-assembled c-axis orientation is established for misfit cobaltate-based films using chemical solution deposition. All samples behave like semiconductors due to the coexistence of Co(3+)/Co(2+) ions, and the resistivity at 350 K is ~47, 39 and 17 mΩ cm for the thin films on SrTiO(3) (100), (110) and (111), respectively, whereas the Seebeck coefficient at 300 K is 97, 89 and 77 μV K(-1). The successful attainment of Bi(2)Sr(3)Co(2)O(y) thin films with self-assembled c-axis orientation will provide an effective prototype for investigation of growth mechanisms in complex oxide thin films with a misfit structure.
authors.affiliation: Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei, 230031, P. R. China. xbzhu@issp.ac.cn
authors.forename: Xuebin
authors.initials: X
authors.lastname: Zhu
authors.forename: Xianwu
authors.initials: X
authors.lastname: Tang
authors.forename: Dongqi
authors.initials: D
authors.lastname: Shi
authors.forename: Hongbin
authors.initials: H
authors.lastname: Jian
authors.forename: Hechang
authors.initials: H
authors.lastname: Lei
authors.forename: Wai Kong
authors.initials: WK
authors.lastname: Yeoh
authors.forename: Bangchuan
authors.initials: B
authors.lastname: Zhao
authors.forename: Jie
authors.initials: J
authors.lastname: Yang
authors.forename: Qi
authors.initials: Q
authors.lastname: Li
authors.forename: Rongkun
authors.initials: R
authors.lastname: Zheng
authors.forename: Shixue
authors.initials: S
authors.lastname: Dou
authors.forename: Yuping
authors.initials: Y
authors.lastname: Sun