Electrical Conduction and Dielectric Properties of the Rb-doped CaCu_3Ti_4O_(12)

摘要

Ca_(1-x)Rb_xCu_3Ti_4O_(12)(x = 0, 0.03, and 0.05) ceramics were synthesized by the sol-gel method. Their microstructure and electrical properties were investigated. In the Rb-doped samples, the Cu-rich and Ti-poor grain-boundary layers are formed, and electrical properties are also changed by doping: With the increase in doping concentration, the grain resistivity and the grain-boundary Schottky potential barrier are changed, the grain-boundary resistivity is enhanced, and the low-frequency dielectric constants and loss are reduced. These results were discussed in terms of the internal barrier layer capacitor (IBLC) mechanism, particularly focusing on the electrical properties in grains and the cationic nonstoichiometry at grain boundaries.