Calorimetric Determination of Heat Capacity, Entropy and Enthalpy of Mixed Oxides in the System CaO–SrO–Bi2O3–Nb2O5–Ta2O5

Abstrakt

Mixed oxides in the system CaO–SrO–Bi2O3–Nb2O5–Ta2O5 possess many extraordinary electric, magnetic and optical properties for which they are used in fabrication of various electronic components. For example Sr2(Nb,Ta)2O7 and (Sr,Ca)Bi2(Nb,Ta)2O9 are used for ferroelectric memory devices, CaNb2O6, Sr5(Nb1–xTax)4O15 and Bi(Nb,Ta)O4 for microwave dielectric resonators and Ca2Nb2O7 as non-linear optical materials and hosts for rare-earth ions in solid-state lasers.

Ternary strontium bismuth oxides SrBi2O4, Sr2Bi2O5, and Sr6Bi2O9 are of considerable interest due to a visible light driven fotocatalytic activity.

Klíčová slova

• Calorimetric
• Determination
• Heat
• Capacity
• Entropy
• Enthalpy
• Mixed
• Oxides
• System
• CaO–SrO–Bi2O3–Nb2O5–Ta2O5