How large can the dielectric constant of pure barium titanate become?

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Figure 1: Ferroelectric properties of barium titanate (BaTiO3). (Left) Above 120° C the structure of the BaTiO3 crystal is cubic, and there is no net polarization of charge; (right) below 120° C the structure changes to tetragonal, shifting the relative positions of the ions and causing a concentration of positive and negative charges toward opposite ends of the crystal. — capacitor dielectric and piezoelectric ceramics Figure 1: Ferroelectric properties of barium titanate (BaTiO₃). (Left) Above 120° C the structure of the BaTiO₃ crystal is cubic, and there is no net polarization of charge; (right) below 120° C the structure changes to tetragonal, shifting the relative positions of the ions and causing a concentration of positive and negative charges toward opposite ends of the crystal.

For pure barium titanate (BaTiO $_{3}$ ), the dielectric constant typically falls within the range of 1,000 to 5,000. While specific values can vary based on conditions—such as the orientation of the applied electric field relative to the crystal axis—it is often cited as being approximately 2,000 at room temperature.12

It is important to note that these values can be significantly higher if the chemical composition is modified; for instance, replacing the titanium ion with zirconium can increase the dielectric constant to as much as 50,000. Additionally, pure barium titanate exhibits a large peak in its dielectric constant near its Curie point, a property that is generally avoided in stable capacitor applications through chemical substitutions.1