Abstract
Temperature evolution of crystal structure of KNO3 embedded into porous glasses with average pore diameters 7 nm, 46 nm and 320 nm have been studied by neutron and X-rays diffraction. For 320 nm samples it is shown that KNO3 phase transition temperatures and their sequence corresponds to the bulk. For 46 nm sample the temperature interval of the ferroelectric phase stability enlarges significantly and there is a temperature range where all three phases coexist. It has been demonstrated that for 7 nm samples ferroelectric phase becomes stable down to 100°K and remains stable after consequent heating-cooling cycles.
Funding
This work is supported by grants of Russian Foundation of Basic Researches (11-02-00739 and 12-02-00230) and Ministry of Education and Science of Russian Federation.