High Dielectric Constant in the Charge‐ordered Manganese Oxide CaMn₇O₁₂

The dielectric properties of mixed‐oxide CaMn 7 O 12 are reported. This compound exhibits a high dielectric constant at room temperature (ε′ r > 10 4 ), for frequencies up to 10 4 Hz, values that make it very attractive for potential applications provided that its rather high losses can be minimized. Complex plane analysis of the obtained data reveal an important extrinsic contribution to these high ε′ r values; and also that the intrinsic dielectric constant of this material is ε′ r,∞ ≈ 30, a value rather high for this type of compounds, that could be related to the electronic process of charge‐ordering present in this oxide below 440 K.