Dielectric and electrical study of zinc copper ferrite nanoparticles prepared by exploding wire technique

The experimental investigation of electrical and dielectric characteristics of spinel Zn-Cu ferrite (ZCFO) nanoparticles, synthesized adopting an exploding wire technique (EWT)-based approach, is reported in this paper. The direct current (DC) electrical parameters of prepared nanoparticles were studied by two-probe method in the range of 300 K (RT) to 423 K. The activation energy for hopping of charge carriers, drift mobility and charge concentration was determined through DC analysis. The attributes of dielectric behavior like dielectric constant (epsilon '), loss tangent (tan delta), dielectric loss (epsilon '') and alternating current (AC) conductivity (sigma(AC)) were measured at various temperatures in the frequency range of 10 Hz-10 MHz. The increase in AC conductivity with frequency, observed in our study, represented the normal behavior of spinel ferrite. The two-layer model based on space charge polarization could satisfactorily elucidate variation in dielectric constant with frequency. The dielectric parameters at different frequencies were also determined in temperature range of 300-673 K. The decrease in DC resistivity as well as the increase in AC conductivity, with rise in temperature, affirms the semiconducting nature of prepared nanoferrite with the band gap energy of 3.16 eV, as calculated through UV-visible analysis. The capacitance of thin grain boundary region (C-gb), grain boundary resistance (R-gb) and relaxation time (tau(g)) of zinc-copper nanoferrite were estimated through Cole-Cole plot analysis.