Dielectric relaxation of Y1−xRxFeO3 (R = Dy, Er, x = 0, 0.5)

• Dielectric properties of Y1−xRxFeO3 (R = Dy, Er, x = 0, 0.5).
• Rietveld refinement of XRD profiles confirm the orthorhombic phase of the materials.
• The relaxation mechanism of the samples is modeled by Cole–Cole equation.
• Activation energy is found to be ∼0.27 eV
• The conduction mechanism in the samples may be due to the polaron hopping based on the electron carriers.

The ceramic samples Y1−xRxFeO3 (R = Dy, Er, x = 0, 0.5) are synthesized by the solid-state reaction technique. The crystal symmetries of the synthesized materials have been obtained from the Rietveld refinement of the X-ray diffraction patterns at room temperature (303 K). The homogeneity of the constituent elements and the grain sizes of the samples are determined by scanning electron microscope study. Impedance spectroscopy study of the samples has been performed in the frequency range from 50 Hz to 1 MHz and in the temperature range from 303 K to 503 K. Dielectric relaxation peaks are observed in the imaginary parts of the spectra. The frequency dependence of real and imaginary parts of dielectric permittivity is analyzed using modified Cole–Cole equation. The temperature dependence relaxation time is found to obey the Arrhenius law having activation energy ∼0.27 eV which indicates that the conduction mechanism in the samples may be due to the polaron hopping based on the electron carriers. The complex impedance plane plots of the samples indicate the presence of both grain and grain-boundary effects and are analyzed by an electrical equivalent circuit consisting a resistance and constant phase element. The frequency dependent conductivity spectra are found to follow the power law.

Rietveld refinement plot for Y1/2Er1/2FeO3. The scanning electron micrograph (SEM) of the sample is shown in the inset.Figure optionsDownload as PowerPoint slide