Comparison of the chemical diffusion of undoped and Nb-doped SrTiO3

✍ Scribed by P. Pasierb; S. Komornicki; M. Rekas

• Publisher: Elsevier Science
• Year: 1999
• Tongue: English
• Weight: 335 KB
• Volume: 60
• Category: Article
• ISSN: 0022-3697
• DOI: 10.1016/s0022-3697(99)00193-6

✦ Synopsis

The re-equilibration kinetics of single crystal and thin films of SrTiO 3 were monitored by measuring electrical conductivity as a function of temperature, T, and oxygen partial pressure, p O 2 , over the ranges: 823 K Ͻ T Ͻ 1173 K and 10 Pa Ͻ p O 2 Ͻ 0.1 MPa. Application of the solution of Fick's second law (with the initial condition: no concentration gradient in specimen and the boundary condition: surface concentration constant) to the kinetic data gave the chemical diffusion coefficient for both oxidation and reduction runs. The chemical diffusion coefficient of thin films (both undoped and Nb-doped SrTiO 3 ) exhibits ca. six orders of magnitude lower values than those of single crystal. This difference was considered in terms of different defect structure of the studied materials.