Influence of Yb2O3 on electrical and microstructural characteristics of CaCu3Ti4O12 ceramics

• Yb atoms may take the place of Ca sites and concentrate at grain boundaries.
• Tiny second phase corresponding to Yb may decrease the grain size.
• Decrease of the grain size leads to the decrease of dielectric constant.
• Yb doping could decrease the dielectric loss of CCTO.

This paper focuses on the remarkable effects of Yb2O3 doping on the microstructure and dielectric characteristics of CaCu3Ti4O12 (CCTO). Samples were prepared by the solid phase reaction method and sintered in air at 1030 °C for 12 h. X-ray diffraction and X-ray photoelectron spectroscopy studies confirm that the primary phase is CCTO. Some Yb3+ ions may substitute into the Ca site at the center or zenith sites of the CCTO lattice hexahedron, while the rest of the Yb atoms may concentrate at grain boundaries. The grain size of Yb2O3-doped CCTO ceramics were examined by scanning electron microscopy and demonstrate sharp grain size reduction with Yb2O3 doping. From dielectric property measurements, the Yb2O3 doping reduces the dielectric constant of CCTO, and the dielectric loss is also reduced.

Some Yb atoms entered in the lattice of CCTO substituted the Ca sites, the rest of Yb atoms concentrated at grain boundaries decreased the grain size. The dielectric constant was decreased by Yb doping. The dielectric loss of the CCTO could be greatly reduced at low frequency.Figure optionsDownload as PowerPoint slide