ACu3Ti4O12氧化物介電性質之研究 (A = Ca, La, Nd, Gd)

Abstract

In recent years, there has been considerable interest in CaCu3Ti4O12 (CCTO), a material with a cubic perovskite-related crystal structure because of its peculiar dielectric property. CCTO is known to exhibit an enormously large low-frequency dielectric permittivity ( is of the order of 104~105). The high dielectric constant persists over a broad temperature range. This dielectric feature makes some of them promising for the applications in various microelectronic devices. In this essay, besides CaCu3Ti4O12, Ca atoms are replaced by some of the rare earth elements. LaCu3Ti4O12, La2/3Cu3Ti4O12, NdCu3Ti4O12, and GdCu3Ti4O12 are first prepared and their properties are also investigated. Several models have been taken to explain their behavior on physics. We investigated the mechanisms that govern these dielectric properties, and analyzed the data of dielectric constants (both real and imaginary part) and loss tangent. The relation between microscopic structure and dielectric properties were discussed, it is realized that high dielectric constant phenomenon can be mainly attributed to the grain and grain boundary effects. Besides, it is found that LaCu3Ti4O12 sintered at 1050 ℃ is provided with very steadily high dielectric constant and low loss factor.