Abstract
The CuFeCr0.5Ni0.5O4 (CFO) compound was synthesized using sol-gel reaction combustion technic. The structural analysis showed that the obtained composites have a polycrystalline nature and the cubic spinel structure (Fd (3) over barm space group). Microstructural analysis revealed the formation of spherical and elongated grains of our sample. The dielectric and electrical transport properties of CuFeCr(0.5)Ni(0.5)O(4 )were investigated in detail by Ac impedance spectroscopy in a wide range of temperature (200-400 K) and frequency (100 Hz to100KHz). Our results show that the electrical modulus and impedance studies confirm the presence of a relaxation phenomenon with non-Debye type in the prepared sample. The activation energy E-dc estimated from the slope of the linear fit plot is equal to 0.158 eV with frequency of 100 Hz and 0.126 eV with frequency of 1 MHz at temperature range 200-400 K. Close activation energies values were found from analyses of relaxation time and dc conductivity indicating that the relaxation and the conduction processes may be attributed to the presence of free carrier charges and impurities at the grain boundaries. The conduction process for samples is described by the NSPT model. The complex impedance analyses and modulus formalism confirm a grain and grain boundaries mechanism contributing to the dielectric properties. The real and the imaginary parts of the impedance are well-fitted to equivalent electrical circuit (R-g + R-gb/ /CPEgb) and we used for modeling the Nyquist data.