Influence of TiO2 addition on the Mg4Nb2O9 ceramic phase and its application in the radiofrequency region

• Published in: Materials today : proceedings 2024-05
• Main Authors: Sales, J.C., Nobrega, F.A.C., do Nascimento, J.P.C., Sales, A.J.M., de Sousa, W.V., Carmo, F.F., Abreu, R.F., Silva, M.A.S., Sombra, A.S.B.
• Format: Article
• Language: English
• Subjects: Complex impedance spectroscopy; Dielectric properties; Mg4Nb2O9 – TiO2 composite
• ISSN: 2214-7853; 2214-7853
• DOI: 10.1016/j.matpr.2024.04.089

In this work, the dielectric properties of (1-x) Mg4Nb2O9 – (x) TiO2 composite ceramics in radiofrequency and the microwave region were evaluated. X-ray diffraction demonstrated that Mg4Nb2O9 (MNO) reacted with TiO2 resulting in the formation of new crystalline phase Mg5(Nb0.625Ti0.375)4O15. Complex Impedance Spectroscopy (CIS) analysis was realized to analysis the electrical properties of materials, whereas was observed that activation energy (Ea) decrease from 1.64 to 1.37 eV with an increase in TiO2 concentration. Temperature capacitance coefficient (TCC) was obtained and showed that at different frequencies all materials could be used as Class 1 ceramic capacitors according to EIA RS-198. In the Microwave region, MNO – TiO2 demonstrated ε’r between 12.07 (MNO) and 14.08 (MNO18T), tan δ values varying of 2.64  × 10-4 (MNO) up to 5.92 × 10−4 (MNOT14). Regarding the temperature coefficient of resonant frequency (τf) was observed that the values decreased with the increase in TiO2, with the value closest to zero being that of pure MNO (τf = −27 ppm.°C−1). The results presented show that materials evaluated could be utilized in devices that can be act in radio frequency (RF) and microwave (MW) regions.