Extended positron‐trapping defects in insulating MgAl₂O₄ spinel‐type ceramics

Abstract

Abstract Extended defects in insulating nanoporous MgAl 2 O 4 spinel‐type ceramics which trap positrons are characterized by positron annihilation lifetime spectroscopy before and after water‐immersion treatment. It is shown that in both cases the same type of positron traps prevails, but positron trapping in defects near grain boundaries occurs more efficiently in water‐moistened ceramics. It is shown the more perfect structure of ceramics, the more considerable changes occur in the positron trapping parameters of water‐moistened ceramics. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)