Self-diffusion mechanism in solid sodium by NMR

Journal Article · Sat Nov 01 00:00:00 EST 1980 · Phys. Rev., B: Condens. Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.22.4247· OSTI ID:7150637

Bruenger, G; Kanert, O; Wolf, D

The self-diffusion mechanism in solid sodium has been determined by means of NMR. For that purpose, the spin-lattice relaxation times T/sub 1/ and T/sub 1rho/ and the Knight shift K of /sup 23/Na in ultrapure sodium have been measured as a function of temperature in the range of 10< or =T< or =371 K (melting point). At all temperatures, the Zeeman relaxation time T/sub 1/ is determined by conduction electrons leading to a volume-corrected Korringa relation of T/sub 1/T=4.68 +- 0.13 K s. In the temperature range 150 --280 K, an additional contribution to the rotating-frame relaxation rate, T/sup -1//sub 1rho/, arising from fluctuations in the nuclear dipole interaction due to atomic self-diffusion is observed. By comparing the motion-induced part of the relaxation rate with the tracer measurements of Mundy, the correlation factor and thus the self-diffusion mechanism in sodium is determined. The following three diffusion mechanism have been assumed to interpret the observed curvature in the Arrhenius plot: (1) a combination of mono- and divacancies; (2) monovacancies alone with a temperature-dependent pre-exponential factor and activation enthalpy; and (3) monovacancies with the possibility of vacancy double jumps. It is found that the temperature dependence of the measured correlation factor is consistent with the simultaneous migration of mono- and divacancies while the other two mechanisms can be ruled out as solely responsible for the observed effects.

• Research Organization: Institut fuer Physik, Universitaet Dortmund, West Germany
• OSTI ID: 7150637
• Journal Information: Phys. Rev., B: Condens. Matter; (United States), Vol. 22:9
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
SODIUM
SELF-DIFFUSION
SODIUM 23
NUCLEAR MAGNETIC RESONANCE
CORRELATIONS
KNIGHT SHIFT
SPIN-LATTICE RELAXATION
TEMPERATURE DEPENDENCE
VACANCIES
ALKALI METAL ISOTOPES
ALKALI METALS
CRYSTAL DEFECTS
CRYSTAL STRUCTURE
DIFFUSION
ELEMENTS
ISOTOPES
LIGHT NUCLEI
MAGNETIC RESONANCE
METALS
NUCLEI
ODD-EVEN NUCLEI
POINT DEFECTS
RELAXATION
RESONANCE
SODIUM ISOTOPES
STABLE ISOTOPES
360104* - Metals &amp; Alloys- Physical Properties