PAL spectroscopy as experimental probe for extended free-volume defects in inorganic glasses and ceramics

Extended free-volume defects trapping positrons are studied in inorganic glasses and functional ceramics using positron annihilation lifetime spectroscopy. Obtained results are treated in terms of general macroscopic approach grounded on physical-chemical properties of the tested materials which depend on the value of free volume content. At the example of chalcogenide glasses of ternary Ge-Sb-S system and spinel-type mixed transition-metal manganite Cu0.4Co0.4Ni0.4Mn1.8O4 and magnesium aluminate MgAl2O4 ceramics, it is shown that strict correlation exists between numerical values of free volumes of potential positron traps and lifetime parameters determined within two-state positron trapping model.