Influence of frequency variations on the dielectric properties of Sm doped Ba4La9.33Ti18O54 dielectric ceramics at various temperatures

The dependence of frequency variations on the dielectric properties of Sm substituted barium lanthanum titanate was investigated. Dielectric ceramics based on the Ba4(La1-ySmy)9.33Ti18O54 system, where y = 0.0, 0.3, 0.5, 0.7, were synthesized and subsequently characterized for their structural and dielectric properties. The temperature dependences of the relative permittivity and the dielectric losses were measured in the frequency range from 10 kHz to 10 MHz, for temperatures ranging from 25 °C to 150 °C. The measurement system consisted of an impedance analyzer and a temperature chamber. Substituting Sm for La was an effective way to stabilize the variations in relative permittivity, within the temperature range of interest. No dielectric anomaly was observed in this temperature range. The temperature coefficient of the resonant frequency improved from 273.9 ppm/°C at y = 0.0 to 53.8 ppm/°C at y = 0.7. The relative permittivity of 90.33 and a dielectric loss of 0.09 were obtained at 25 °C for y = 0.5 at 10 MHz; the temperature coefficient of the resonant frequency was 106.8 ppm/°C. The materials under investigation have high relative permittivities, remaining constant under temperature variation, which therefore makes them suitable for applications in communication devices.