•W. Sprengel¹, V. Barbe¹, S. Herth^1,2, O. Gutfleisch³, R. Würschum⁴ und H.-E. Schaefer^1
1Institut für Theoretische u. Angewandte Physik, Universität Stuttgart, 70550 Stuttgart
²Institut für Nanotechnologie, Forschungszentrum Karlsruhe GmbH, 76021 Karlsruhe
³Leibniz-Institut für Festkörper- und Werkstoffforschung Dresden, 01171 Dresden
⁴Institut für Technische Physik, Technische Universität Graz, 8010 Graz, Österreich

For nanocrystalline Nd-rich Nd₂Fe₁₄B the grain-boundary self-diffusivities D_GB of ⁵⁹Fe and ¹⁴⁷Nd were studied by the radio tracer technique. In the case of ⁵⁹Fe the temperature dependence of the product of the interface thickness and the interface diffusion coefficient, dD_GB, shows a sharp increase for temperatures above 951 K where a liquid grain-boundary phase has been reported. Below 951 K the temperature dependence of the ⁵⁹Fe diffusivity can be described by an Arrhenius type behavior [1]. First results of the ¹⁴⁷Nd diffusion are presented.