The frequency-dependent dielectric relaxation of calcium-iron-antimonate $\left[\mathrm{Ca}\left({\mathrm{Fe}}_{1∕2}{\mathrm{Sb}}_{1∕2}\right){\mathrm{O}}_3\right]$ (CFS) ceramic, synthesized by a solid-state reaction technique is investigated in the temperature range from $143\text{to}463\mathrm{K}$ by alternating-current impedance spectroscopy. The x-ray diffraction of the sample at room temperature shows a monoclinic phase. Using Cole-Cole model, an analysis of the imaginary part of the dielectric permittivity with frequency is performed assuming a distribution of relaxation times. The activation energy calculated from the frequency dependence of loss spectra is found to be $\simeq 0.60\mathrm{eV}$, which suggests that the bulk conduction in CFS is due to polaron hopping based on the electron carriers. The scaling behavior of the imaginary part of the electric modulus $\left(M^{″}\right)$ suggests that the relaxation describes the same mechanism at various temperatures. We studied the electronic structure of the CFS using x-ray photoemission spectroscopy (XPS). The XPS spectrum was analyzed by the first-principles full-potential linearized augmented plane wave method.

• Received 5 January 2007
• Publisher error corrected 22 October 2007

DOI:https://doi.org/10.1103/PhysRevB.76.155113