  The dielectric constant of CaCu3Ti4O12 is measured with a different electrode
geometry than previous measurements. Similar colossal values are obtained
showing that they are "intrinsic" to the material. We show that in braced
structures such as CaCu3Ti4O12, a small concentration O(10-3) of defects, which
disrupt the bracing and relax between different equivalent configurations, can
lead to colossal dielectric constants above a characteristic temperature. The
dielectric constant e(w,T) has a frequency and temperature dependence of the
same form as found experimentally.
