Anomalous thermal hysteresis in dielectric permittivity of CaCu3Ti4O12

We herein report an anomalous thermal hysteresis in dielectric permittivity in CaCu3Ti4O12. The anomalous behavior was well explained in terms of the low-temperature Maxwell–Wagner relaxation induced by frozen carriers. A multirelaxation mechanism, i.e., the coupling of the dipole relaxation to the frozen carrier-induced and blocked carrier-induced Maxwell–Wagner relaxations in the low-temperature and high-temperature regions, respectively, is proposed to be the origin of the colossal dielectric constant.