Effect of oxygen content on dielectric characteristics of Cr-doped LaTiO_x

The ceramics La_0.85Cr_0.15TiO_x and La_0.7Cr_0.3TiO_x are prepared by conventional solid-state reaction method. The dielectric properties of Cr-doped LaTiO_x as a function of frequency (0.1 kHz ≤ f ≤ 1 MHz) and temperature (77 K ≤ T ≤ 360 K) are studied. The blocks are then annealed in a flowing O₂ or Ar/H₂ to convert their oxygen content and the tests mentioned above are performed. The highly oxygenated samples exhibit extremely high low-frequency dielectric constants at room temperature (~10⁶). The results show that the oxygen stoichiometry could significantly influence the dielectric properties of Cr-doped LaTiO_x.