Issue 43, 2008

Impurity diffusion of 141Pr in LaMnO3, LaCoO3 and LaFeO3 materials

Abstract

The impurity diffusion of Pr3+ in dense polycrystalline LaMnO3, LaCoO3 and LaFeO3 was studied at 1373–1673 K in air in order to investigate cation diffusion in these materials. Cation distribution profiles were measured by secondary-ion mass spectrometry and it was found that penetration profiles of Pr3+ had two distinct regions with different slopes. The first, shallow region was used to evaluate the bulk diffusion coefficients. The activation energies for bulk diffusion of Pr3+ in LaMnO3, LaCoO3 and LaFeO3 were 126 ± 6, 334 ± 68 and 258 ± 75 kJ mol−1, respectively, which are significantly lower than previously predicted by atomistic simulations. The bulk diffusion of Pr3+ in LaMnO3 was enhanced compared to LaCoO3 and LaFeO3 due to higher concentrations of intrinsic point defects in LaMnO3, especially La site vacancies. Grain-boundary diffusion coefficients of Pr3+ in LaCoO3 and LaFeO3 materials were evaluated according to the Whipple–Le Claire equation. Activation energies for grain-boundary diffusion of Pr3+ in LaCoO3 and LaFeO3 materials were 264 ± 41 kJ mol−1 and 290 ± 36 kJ mol−1 respectively. Finally, a correlation between activation energies for cation diffusion in bulk and along grain boundaries in pure and substituted LaBO3 materials (B = Cr, Fe, Co) is discussed.

Graphical abstract: Impurity diffusion of 141Pr in LaMnO3, LaCoO3 and LaFeO3 materials

Article information

Article type
Paper
Submitted
30 May 2008
Accepted
25 Jul 2008
First published
24 Sep 2008

Phys. Chem. Chem. Phys., 2008,10, 6544-6552

Impurity diffusion of 141Pr in LaMnO3, LaCoO3 and LaFeO3 materials

M. Palcut, J. S. Christensen, K. Wiik and T. Grande, Phys. Chem. Chem. Phys., 2008, 10, 6544 DOI: 10.1039/B808789J

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