Enhanced dielectric responses in Mg-doped CaCu3Ti4O12

We report the effects of the Mg doping on the dielectric properties of CaCu3Ti4O12 in the frequency range of 200 Hz-200 kHz and in the temperature range of 58-473 K. It is found that the incorporations of Mg2+ result in increases in the dielectric constant by 12%-20% and decreases in the dielectric loss by 41%-64% (with the minimum of 0.042 for CaCu2.7Mg0.3Ti4O12) at room temperature and at 1 kHz. The x-ray photoemission spectroscopy measurements reveal that the content of Cu3+ increases with the increasing concentration of Mg2+. The enhanced dielectric response may be related to the influence of Cu3+ and/or Mg2+. In other words, Mg2+ is an effective ion to optimize the dielectric properties of CaCu3Ti4O12. (c) 2008 American Institute of Physics.