Dielectric Relaxation of CaCu$_3$Ti$_4$O$_{12}$ synthesized from a pyrolysis method*

Giant dielectric constant material CaCu$_3$Ti$_4$O$_{12}$ has been synthesized by using a pyrolysis method. A stable solution was made by dissolving calcium nitrate, copper nitrate, and titanium isopropoxide in 2-methoxyethanol; the solution was then heated at 500 and 700 $^o$C for 2 hours to obtain a pure phase of CaCu$_3$Ti$_4$O$_{12}$. The frequency and temperature dependences of dielectric permittivity were examined in the ranges of 10$^{-1}$$\sim$10$^{6}$ Hz and -150$\sim$200 $^o$C. We found that the dielectric properties of the sample were the same as those made from solid state reaction. Specifically, there is a Debye-like relaxation at low temperature and its giant dielectric constant about 11000 is independent of the temperature and frequency over a wide range.