Effect of morphology and particle size on the electrical properties of nano-nickel ferrite

Abstract

Four powder samples of Nickel ferrite (NiFe2O4) with different morphology and nanoparticle size have been synthesized by various methods: electrospinning, hydrothermal, green, and sol-gel. Through the use of XRD, FT-IR, SEM, TEM, and BET techniques, the prepared powders were characterized. The produced ferrite displayed a cubic spinel phase with various nanofiber, nanotube, nanorod, and nanosphere morphological structures. The electrical conductivity values for each sample increased with increasing temperature indicating the semiconducting behavior of all samples. The conductivity values were found to be dependent on each nanoparticle's size and morphology. The variation of dielectric constant (ε′), dielectric loss (ε′′), and ac conductivity for the investigated samples at different temperatures and frequencies has been studied. Both dielectric constant (ε′) and dielectric loss (ε′′) were decreased with the increase of frequency while A.C. conductivity increased. Knop's phenomenological theory explains the frequency variation of (ε′ and ε′′). The hopping of electrons and holes is suggested to be the electrical conduction mechanism.