High-Temperature Electric Properties and X-ray Photoemission Spectra of Layered Co-Based Oxides Bi<,2-x>La<,x>Sr<,2>Co<,2>O<,8-δ>

摘要：

Layered Co-based ceramics with a nominal composition Bi<,2-x>La<,x>Sr<,2>Co<,2>O<,8-δ>(x=0.0, 0.4, 0.8, short by BLC-222) were prepared using conventional solid state reaction method. X-ray photoemission spectroscopy (XPS) was used to investigate their electronic structures. The cobalt ions are highly mixed valences of Co<3+> and Co<4+>. The fraction of Co<4 +> almost keeps unchanged with the increase of x. The O-1s photoemission spectra show that there are lattice oxygen and chemical absorbed oxygen in all the samples. The substitution of Bi <3+> by La<3+> results in a change from metallic-like behavior to semiconductor behavior. This abnormal phenomenon means that La<3+> plays a key role in effecting the electrical transport property of BLC-222. The O-Co covalence bond is strengthened by the increase of La<3+>, which results in the decrease of conductivity.

关键词： layered Co-based ceramic thermalelectric XPS BC-222 rare earths

作者: Li Zhonghua(李中华) Chen Gang(陈刚) Pei Jian(裴健) Liu Pusheng(刘璞生)

作者单位: Department of Applied Chemistry, Harbin Institute of Technology, Harbin 150001, China Department of Applied Chemistry, Harbin Institute of Technology,Harbin 150001, China

会议类型: 国际会议

会议名称: 第五届国际稀土开发与应用研讨会(The Fifth International Conference on Rare Earth Decelopment and Applicatin)

会议地点: 包头

会议语种:英文

页码: 301-304

在线出版日期: 2007-08-07（万方平台首次上网日期，不代表论文的发表时间）