Structural, temperature/frequency dependence of dielectric, electrical and magnetic properties of Ni-doped inverse spinel CuFe2O4 nanoferrite

Nickel (Ni)-doped Copper ferrite (inverse spinel ferrite) Cu1_XNiXFe2O4 (x = 0.00, 0.05, 0.10, 0.15) are synthesized via sol-gel auto-combustion method. The phase formation is examined by X-ray diffraction technique which confirms the tetragonal structure of all samples at room tem-perature. Field Emission Scanning Electron Microscope (FESEM), dielectric, conductivity, impedance and modulus analysis are also carried out to study the morphology and the electrical properties of the ferrites. Dielectric study (Er vs. T) confirms the presence of frequency dependent dielectric relaxation peak. The temperature (T-m) at which the value of epsilon(r) is maximum shift towards higher temperature as frequency increases. Dielectric properties have been improved after Ni is doped into Copper ferrite. Both ac and dc conductivity confirms the NTCR behavior in the ferrites. Frequency variation of ac conductivity follows the Jonscher's power law and the conduction mechanism in the ferrites is well explained by Correlated barrier hopping (CBH) model. Nyquist plot (Z ' ' vs. Z ' ) reveals combine contribution of both bulk and grain boundary effects in the ferrites. DC conductivity (sigma(dc)) and the relaxation time (tau) obeys Arrhenius type behavior and the modulus study validates the existence of non-Debye type of relaxation. The detail complex impedance and modulus analysis support the usage of many technological applications. Vibrating Sample Magnetometer (VSM) analyzer shows the soft magnetic nature of as-prepared ferrites and has the potential application towards magnetic storage devices and field sensor. Enhancement of saturation magnetization (MS) is also noticed as Ni content is increased.