CaTiO3 RELATED MATERIALS FOR RESONATORS

Abstract

Ceramics of Ca0.95M0.05(Ti0.95Li0.05)O2.85F0.15 (M = Ca, Sr, Pb) are prepared from mixtures of CaTiO3, MF2 and LiF powders by sintering at 950°C for 4 hours in free-air. The samples are investigated by X-ray diffraction, scanning electron microscopy, differential scanning calorimetry and dielectric measurements. The phase transitions of pure CaTiO3 are strongly influenced by the incorporation of the fluoride mixture MF2 + LiF into the host lattice whereas the orthorhombic symmetry at room temperature is not at all affected by the chemical substitutions Ca-M, Ti-Li and O-F. The dielectric permittivity e'r and losses tand are slightly dependent of temperature between 20°C and 200°C. At room temperature, e'r is stable over a large frequency range with tand < 1%. The Ca0.95M0.05(Ti0.95Li0.05)O2.85F0.15 (M = Ca, Sr, Pb) oxyfluorides are promising materials to manufacture resonators.

Keywords

• CaTiO3
• Oxyfluorides
• Phase transitions
• Dielectric characteristics