| Various mol% of Nb20 5 were incorporated into BaTi03 during
its preparati~n in the form of BaTiO(C20 4)z.4H20. For a critical
concentration of 0.25 mol% Nb20 5, the dielectric constant of
the material was· found to increase drastically to a value of
80,000 at room temperature at 1 KHz frequency. On adding 2
mol% excess Ti to the calcined powder, the dielectric constant
reached a value of 6.5 x 105
• The Curie point of the critically
doped samples was ll6°C, i.e. l2°C below that of undoped
samples. No change in dielectric constant or Curie point compared
to undoped samples was observed if the excess Ti was
incorporated during precipitation. The high effe(·tive value of
the dielectric constant is possibly indicative of a grain boundary
harrier layer capacitive effect. |
