Perovskite-like structure CaCu₃Ti₄O₁₂ (CCTO) dielectric ceramic has been paid much attention in the field of materials science and application for its colossal dielectric constant, independence of dielectric properties on the frequency and temperature in a wide range, and nonlinear behaviors. Various theories and models which are used to explain the original of colossal dielectric constant of CCTO are compared, among which the internal barrier layer capacitance (IBLC), the most reasonable model is claimed in detail. Preparing methods, preparing conditions and various modification methods for preparing CCTO and improving the dielectric properties are discussed. Ion-doping is the most popular way to decrease the dielectric loss of CCTO. The effects of ion-doping depend on the ionic radius, ionic valence and so on. It is a promising way to prepare the 0-3 composites by using ceramic as filler and polymer as matrix. The research progress of CCTO/polymer composites is discussed here. And the prospects of CCTO is put forward.

Contents
1 Introduction
2 Origin of giant dielectric constant of CCTO
2.1 Classical model
2.2 Internal barrier layer capacitance (IBLC) model
3 Preparation of CCTO
3.1 Preparation of CCTO powder
3.2 Method for reducing sintering temperature and time of CCTO
3.3 Preparation of CCTO film
4 Improvement of the properties of CCTO
4.1 A or B site doping of CCTO
4.2 Substitution of CCTO
5 CCTO/polymer composite
5.1 CCTO/polymer composite and mixture model
5.2 Improvement of the interfacial properties of CCTO/polymer
5.3 Three-phase composite
6 Conclusion