Abstract
Conductivity behavior during the temperature cycling through the phase transition temperature of VO2 (Tt=68°C) was investigated in glass-ceramics based on VO2 and vanadium phosphate glass (VPG) for compositions without and with Cu and SnO2 additives. Copper and SnO2 additives stabilize the conductivity of glass-ceramics at temperature cycling. For ceramics (wt%) (80−y)VO2–5Cu–15VPG–ySnO2 the best stabilizing effect takes place when SnO2 content is in the interval 35wt%<y<50wt%. Ceramics with such SnO2 content keeps a stable value of the conductivity change (∼102) in the vicinity of VO2 phase transition temperature and shows the conductivity decrease no more than of 2.5 times after 3000 thermal cycles. The reasons of conductivity stabilizing in VO2-based glass-ceramics with additives of Cu and SnO2 are being discussed. The analysis resting on the percolation theory has shown the increase of conductivity stability in VO2-based glass-ceramics when the VO2 volume fraction and the average size of VO2 crystallites decrease and the ceramics surface tension increases.
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