Dielectric behavior and a. c. conductivity studies on Co0.4Ni0.6Fe2O4 nanoparticles synthesized via combustion method

Cobalt-Nickel (Co_0.4Ni_0.6Fe₂O₄) ferrite nanoparticles were prepared by solution combustion method using cobalt nitrate & nickel nitrate as oxidizers and urea as a fuel. The structures of the sample were studied with X-ray diffraction (XRD) using Cu-Kα radiation. The X-ray diffraction analysis revealed the nanocrystalline nature in the prepared ferrite samples. The dependence of dielectric properties such as dielectric constant (ε\´) and dielectric loss factor (ε"), dielectric loss tangent (tanδ) and the a. c. conductivity (σ) on the frequency has been undertaken over a wide range of frequencies (100Hz- 5MHz) at room temperature. The dielectric constant (ε\´) and dielectric loss factor (ε") were found to decrease initially with an increase in frequency and reached a constant value at higher frequency, exhibiting a frequency-independent behavior at higher frequencies. The dielectric loss tangent (tanδ) was found to decrease with an increase in the frequency. A. c. conductivity of the Co-Ni nanoferrite was found to increase with the increase in the frequency. The electrical conduction mechanism in the Co- Ni nanoferrite is found to be in accordance with the electron hopping model.