Comparison of Grain Boundary Structure in Metals and Semiconductors as Probed by Positrons

Abstrakt

Vacancy behavior and positron trapping at selected grain boundaries in iron, nickel, and zirconia are investigated theoretically. It is found that the grain boundary vacancy loses its free volume in metals at moderate temperatures whereas it is kept up to very high temperatures in zirconia.

The consequences of these findings for positron annihilation studies of nanocrystalline materials are discussed.

Klíčová slova

• initio molecular-dynamics
• spectroscopy