Phase composition and microwave dielectric properties of Ca0.128Ba0.032Sm0.46Li0.3TiO3 ceramics with alumina addition

Effects of ion polarizability and oxygen vacancy on microwave dielectric properties of fluorite‐structured Ce1−xCaxO2−x

“…These phenomena are normal, and the two processes are caused by the reduction of pores and the abnormal growth of grains during sintering. 22,23 Generally, intrinsic factors, including structural characteristics and polarizability, as well as extrinsic factors, including secondary phase and porosity, are two aspects that determine the permittivity and quality factor of ceramics. 24,25 The effects of porosity and the second phase in Ce 1−x Ca x O 2−x (x = 0-0.20) ceramics are negligible because of the high relative density (>97%, Figure 3) and the absence of the second phase.…”

“…With increased sintering temperature increases, the trends of ε r and Q × f are similar to those of density, as shown in Figure 5. These phenomena are normal, and the two processes are caused by the reduction of pores and the abnormal growth of grains during sintering 22,23 . Generally, intrinsic factors, including structural characteristics and polarizability, as well as extrinsic factors, including secondary phase and porosity, are two aspects that determine the permittivity and quality factor of ceramics 24,25 .…”

Acceleration of optimizing the dielectric properties of (Ca0.7Nd0.2)1−x(Li0.5Nd0.5)xTi1−y(Mg1/3Nb2/3)yO3 with the aid of machine learning

“…In addition to the requirement for a high dielectric constant, other two key properties of the ceramics in the GHz frequency range are also highly concerned: a high quality factor ( Q × f , Q is approximately equal to 1/tan δ ) to improve selectivity and a near‐zero temperature coefficient of resonance frequency ( τ f ) to achieve temperature stability (most microwave devices applications require τ f ≤ ±10 ppm/°C) 5 . Previous studies have shown that even small variations in composition can dramatically affect the dielectric properties of ceramics, 6–8 suggesting the significant challenge of identifying the optimal composition for achieving the desired properties. Meanwhile, researchers have also noted the coupling relationship among ε r , Q × f , and τ f 9 .…”