Diffusion processes in solid Li-Mg and Li-Ag alloys and the spin-lattice relaxation of ⁸Li

authored by

A. Korblein, P. Heitjans, H.-J. Stockmann, F. Fujara, H. Ackermann, W. Buttler, K. Dorr, H. Grupp

Abstract

The spin-lattice relaxation (SLR) of polarised radioactive ⁸Li nuclei in solid Li-based alloys containing 2-11 at.% Mg and 1.6-10 at.% Ag was measured via their asymmetric beta -decay radiation. For temperatures T<200K SLR is due to conduction electrons only, and the Korringa relation is found to hold in the concentration range covered. For T=200-450K, SLR is additionally influenced by atomic diffusion. The diffusional contribution consists of a dipolar part as in pure Li and a quadrupolar part induced by the solute ions. The analysis is based on the concept of two-exponential SLR for spin I=2. In Li-Mg the self-diffusion of Li and the diffusion of the solute ions are found to be slowed down on alloying. The ratio of the jump rates of Li and Mg appears to be determined simply by their atomic masses. In the case of the dilute alloy Li-1.6 at.% Ag, which is amenable to theoretical diffusion models, comparison with tracer results favours an interstitial-vacancy pair mechanism. In the framework of this model Ag is found to diffuse faster than Li.

External Organisation(s)

Philipps-Universität Marburg

Type

Article

Journal

Journal of Physics F: Metal Physics

Volume

15

Pages

561-577

No. of pages

17

ISSN

0305-4608

Publication date

1985

Publication status

Published

Peer reviewed

Yes

ASJC Scopus subject areas

General Engineering, Physics and Astronomy (miscellaneous), Metals and Alloys

Electronic version(s)

https://doi.org/10.1088/0305-4608/15/3/011 (Access: Unknown)