  The glasses in the system (100-x)TeO2-xCaCu3Ti4O12, (x=0.25 to 3 mol %) were
fabricated. The color varied from olive green to brown as the CaCu3Ti4O12
(CCTO) content increased in TeO2 matrix. The X-ray powder diffraction and
differential scanning calorimetric analyses that were carried out on the
as-quenched samples confirmed their amorphous and glassy nature respectively.
The dielectric constant and loss in the 100 Hz-1MHz frequency range were
monitored as a function of temperature (50-400oC). The dielectric constant and
the loss (D) increased as the CCTO content increased in TeO2 at all the
frequencies and temperatures under investigation. Further, the effective
dielectric constant and D were found to be frequency independent in the
50-200oC temperature range. The value obtained for the loss at 1MHz was 0.0019
which was typical of low loss materials, and exhibited near constant loss (NCL)
in the 100Hz-1MHz frequency range. The electrical relaxation was rationalized
using the electric modulus formalism. These glasses may be of considerable
interest as substrates for high frequency circuit elements in conventional
semiconductor industries owing to their high thermal stability.
