Published online by Cambridge University Press: 26 February 2011
Decades of work by a wide variety of techniques were required to establish unambiguously the essential role of simple – and sometimes not so simple – “point” defects in mediating bulk diffusion in crystalline solids. Amorphous solids present new problems for establishing basic diffusion mechanisms. Most experimental techniques which work well for study of diffusion in crystalline solids are useless for study of amorphous materials because of their inherent nonequilibrium structures. A survey of some current results also gives a strong impression that more complex basic mechanisms than simple point defects may be required to account for volume diffusion in these materials.