Evaluation of the effect of the addition of TiO2 on the dielectric behaviour of YNbO4 ceramic using impedance spectroscopy

The present article evaluates the effect of the addition of TiO2 on the dielectric properties in the radiofrequency region of the YNbO4 ceramic matrix. X-ray diffraction (XRD) showed that the YNT (Y(Nb0.5Ti0.5)2O6) phase formed from the reaction between YNbO4 (YNO) and TiO2 in the investigated composites. Complex impedance spectroscopy (CIS) analysis was utilized and it was observed that the activation energy (Ea) values of the materials varied between 1.13 and 2.31 eV. Nyquist diagrams were fitted for the materials using three associations of resistor-constant phase element (R-CPE), with an exception for the YNO40 composite that used only two associations. All compositions presented values of n in the range of 0.6 ≤ n ≤ 1 for grain resistance (Rg) and grain boundary resistance (Rgb), indicating a capacitive character. Temperature capacitance coefficient (TCC) values were also calculated. At many frequencies, it was observed that the composites presented values in the range of ± 1500 ppm °C−1, indicating that the evaluated systems could be employed as Class 1 capacitors according to EIA RS-198.