%0 Journal Article
%T Structural Transitions of Silicate Nanocrystals in the Glass
%J American Journal of Materials Science
%@ 2162-8424
%D 2012
%I 
%R 10.5923/j.materials.20120201.07
%X The temperature dependences of resistivity and thermopower measurements reveal that nanocrystals of silicates in lead-silicate glass of various compositions undergo structural transitions in the temperature range of 800 每 1000 K. The diameter of these nanocrystals estimated from Scherrer＊s formula is about 0.8 每 1.6 nm and each nanocrystal consists of 8 - 64 unit cells. Structure transitions are detected as sharply maxima of resistivity 老 and thermopower S at temperature T = 800 每 100 K. Lead-silicate glass was doped by RuO2 up to 16 weight% to facilitate the measurements of the 老 and the S. The doped lead-silicate glass has a metal-like behavior at the room temperature: the temperature dependences 老(T) and S(T) are very slow, the value of the S is typical for metals (few and tens of 米V/K). Beyond the maximum of the resistance (temperature T > 1000 K) doped lead-silicate glass turns into typical semiconductor having energy gap about 0.05 每 1.5 eV depending on the composition of the glass. Anomalous thermal expansion of the RuO2 relict crystals is detected at the temperatures of 800 每 1000 K as well.
%K structure transitions in nanocrystals
%K silicate glass
%K thermopower
%K resistivity
%K doping
%K thermal expansion
%U http://article.sapub.org/10.5923.j.materials.20120201.07.html