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

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

doi:10.1039/B418824A

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

Karsten Gömann,*^a Günter Borchardt,^a Michał Schulz,^a Anissa Gömann,^b Wolfgang Maus-Friedrichs,^b Bernard Lesage,^c Odile Kaïtasov,^d Susanne Hoffmann-Eifert^e and Theodor Schneller^f

Author affiliations

* Corresponding authors

^a Institut für Metallurgie, Technische Universität Clausthal, Robert-Koch-Str. 42, Clausthal-Zellerfeld, Germany
E-mail: karsten.goemann@tu-clausthal.de
Fax: +49 5323 72-3184
Tel: +49 5323 72-3688

^b Institut für Physik und Physikalische Technologien, Technische Universität Clausthal, Leibnizstr. 4, Clausthal-Zellerfeld, Germany

^c Laboratoire d’Etude des Matériaux Hors Equilibre, Université Paris-Sud, Orsay Cedex, France

^d Centre de Spectrométrie Nucléaire et de Spectrométrie de Masse, Université Paris-Sud, Orsay Cedex, France

^e Institut für Festkörperforschung, Forschungszentrum Jülich, Jülich, Germany

^f Institut für Werkstoffe der Elektrotechnik II, RWTH Aachen, Sommerfeldstr. 24, Aachen, Germany

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.

Article information

https://doi.org/10.1039/B418824A

Article type

Paper

Submitted

15 Dec 2004

Accepted

03 Mar 2005

First published

21 Mar 2005

Download Citation

Phys. Chem. Chem. Phys., 2005,7, 2053-2060

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

K. Gömann, G. Borchardt, M. Schulz, A. Gömann, W. Maus-Friedrichs, B. Lesage, O. Kaïtasov, S. Hoffmann-Eifert and T. Schneller, Phys. Chem. Chem. Phys., 2005, 7, 2053 DOI: 10.1039/B418824A

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