Dielectric properties of CaCu3Ti4O12 ceramics modified by SrTiO3

In this letter, the dielectric properties of CaCu3Ti4O12 ceramics modified by SrTiO3 have been investigated. These ceramics were prepared successfully by conventional ceramic processing. X-ray diffraction results show that the ceramics with SrTiO3 sintered at 1060 degrees C for 3 h are mixed phase and consist of CaCu3Ti4O12 and SrTiO3. The change of dielectric constant is explained well by Lichtenecker's logarithmic law of composite. And the reduction in dielectric loss is attributed to the increase of grain boundary resistance according to internal boundary layer capacitor model, with the increase of SrTiO3. When CaCu3Ti4O12/SrTiO3=6/4 (volume ratio), an optimum component was obtained, exhibiting a high dielectric constant of about 2000 and a low dielectric loss (<0.03) with a good temperature stability from -55 degrees C to 150 degrees C at 1 kHz. (C) 2007 Elsevier B.V. All rights reserved.