Rutile (In0.5Ta0.5)0.1Ti0.87O1.88F0.12 ceramics with excellent dielectric performance and thermal stability sintered at 1220 °C

TiO 2 -based colossal dielectric ceramics have emerged as a prominent research focus in recent years. However, their further applications have been constrained by several key limitations, including the requirement of high sintering temperature (>1400 °C), relatively high dielectric loss (>0.05, 1 kHz), and temperature stability (<200 °C). This study reports rutile (In 0.5 Ta 0.5 ) 0.1 Ti 0.87 O 1.88 F 0.12 ceramics at 1220 °C sintering using 12 % InF 3 as the acceptor In 3+ source, which exhibits a colossal dielectric constant (1.1 × 10 5 ) and an ultra-low dielectric loss (0.0071) at 1 kHz and room temperature, even loss values below 0.04 (20 Hz - 100 kHz). Notably, the thermal stabilities (10 kHz, 100 kHz) simultaneously satisfy X9E (Δε r /ε 25   °C  ≤ ±4.7 %) above 300 °C. F − not only supplies electrons to enhance the semiconductivity of grains, but also decreases the oxygen vacancy and average grain size (270 ± 12.53 nm) to improve grain boundaries resistances, which reduces dielectric loss and enhances frequency and temperature stabilities. As a result, the dielectric mechanism is mainly related to internal barrier layer capacitor (IBLC) and high grain boundary resistance. Therefore, this strategy provides a creative design for developing TiO 2 -based ceramics.