Phenomenon of spontaneous loss of polarization in some porous dielectrics

Recently we have observed that porous CsI prepared by thermal evaporation spontaneously loses its polarization faculty with the elapse of time. In this paper the phenomenon of spontaneous polarization faculty loss (SPFL) of porous CsBr is investigated and compared with that for porous CsI under the same experimental conditions. It is assumed that the SPFL phenomenon can be explained by structural modification of these porous materials after evaporation as well as by the decrease of their forbidden zone—analogously to crystallization of Ge amorphous thin films prepared by vapour deposition and carbon nanotubes, respectively.