Dielectric and Electrical Transport Properties of the Fe3+-doped CaCu3Ti4O12

CaCu3-xFexTi4O12 (x=0, 0.015, 0.03, 0.045, 0.06) ceramics were synthesized by sol-gel method. The electrical conduction and dielectric measurements show that the doping of a very small amount of Fe3+ ions greatly reduces the low-frequency dielectric constants and leakage, and enhances grain resistivity. For the doped samples, the appearance of the strong low-frequency peaks in the spectra of dielectric loss confirms that the doping of Fe3+ ions induces the contact-electrode effect on ceramic surface. These great changes of electrical properties may originate from the reduced amount of oxygen vacancies by doping Fe3+.