Phys Chem Chem Phys. 2005 May 07;7(9):2053-60. doi: 10.1039/b418824a.

Sr diffusion in undoped and La-doped SrTiO3 single crystals under oxidizing conditions.

Physical chemistry chemical physics : PCCP

Karsten Gömann, Günter Borchardt, Michał Schulz, Anissa Gömann, Wolfgang Maus-Friedrichs, Bernard Lesage, Odile Kaïtasov, Susanne Hoffmann-Eifert, Theodor Schneller

PMID: 19787911 DOI: 10.1039/b418824a

Abstract

Strontium titanate SrTiO3(100), (110), and (111) single crystals, undoped or donor doped with up to 1 at% La, were isothermally equilibrated at temperatures between 1523 and 1773 K in synthetic air followed by two different methods of Sr tracer deposition: ion implantation of 87Sr and chemical solution deposition of a thin 86SrTiO3 layer. Subsequently, the samples were diffusion annealed under the same conditions as before. The initial and final depth profiles were measured by SIMS. For strong La-doping both tracer deposition methods yield similar Sr diffusion coefficients, whereas for weak doping the tracer seems to be immobile in the case of ion implantation. The Sr diffusivity does not depend on the crystal orientation, but shows strong dependency on the dopant concentration supporting the defect chemical model that under oxidizing conditions the donor is compensated by Sr vacancies. A comparison with literature data on Sr vacancy, Ti, and La diffusion in this system confirms the concept that all cations move via Sr vacancies. Cation diffusion is several orders of magnitude slower than oxygen diffusion.

Publication Types

• Journal Article
• Research Support, Non-U.S. Gov't