Electric, dielectric and AC electrical conductivity study of Al3+ substituted barium hexaferrite nanoparticles synthesized by Sol-gel auto-combustion technique

Abstract Al3+ substituted barium hexaferrite BaFe12-xAlxO19 (where × x = 0.00, 0.25, 0.50, 0.75,1.00) nanoparticles have been prepared by sol–gel auto combustion technique. Two probe method is used to study the electrical resistivity and dielectric properties of aluminium substituted barium hexaferrite. The DC electrical resistivity reveals that the electrical resistivity as well as the activation energy increases with increase in Al3+ content x. On the basis of Maxwell-Wagner and Koop’s theory the dielectric parameters such as dielectric constant (e′), dielectric loss (e″) and dielectric loss tangent (tanδ) with frequency are discussed. The dielectric parameters decreases with increase in Al3+ content x. The room temperature AC electrical conductivity measurements were carried out at different frequencies (20 Hz −1 MHz). The experimental results indicate that AC electrical conductivity (σac) increases with increase in the frequency, indicating semiconducting behaviour of the samples. The AC impedance spectroscopy technique is used to study internal grain resistance and grain boundary distribution of the prepared aluminium substituted barium hexaferrite samples.