An anion substitution route to low loss colossal dielectric CaCu3Ti4O12

An anion substitution route was utilized for lowering the dielectric loss in CaCu3Ti4O12 (CCTO) by partial replacement of oxygen by fluorine. This substitution reduced the dielectric loss, and retained a high dielectric constant that was essentially temperature independent from 25 to 200 °C. In particular, CaCu3Ti4O11.7F0.3 exhibited a giant dielectric constant over 6000 and low dielectric loss below 0.075 at 100 kHz within a temperature range of 25–200 °C. Fluorine analysis confirmed the presence of fluorine in all samples measured.