ABSTRACT Defect engineering provides an effective means of tuning the charge transport in ferrimagnetic oxides. Here, we present a comparative study of M‐type (BaFe 12 O 19 , SrFe 12 O 19 ) and W‐type (BaCo 2 Fe 16 O 27 , BaZn 2 Fe 16 O 27 ) hexaferrites synthesized via sol–gel auto‐combustion. Using XRD, SEM, TEM, dielectric measurements, and current–voltage measurements, lattice defects are linked to charge‐carrier conduction pathways. XRD confirmed phase‐pure hexagonal structures with nanocrystallite sizes of 33–36 nm. High‐resolution TEM revealed edge dislocations and planar strain fields in BaFe 12 O 19 , along with stacking‐fault arrays in BaCo 2 Fe 16 O 27 , which create localized strain‐induced potential fluctuations. The presence of dislocations and oxygen‐vacancy defects promotes field‐assisted thermionic emission with trap densities of ∼10 16 cm −3 and earlier onset of space‐charge‐limited conduction. Dielectric spectroscopy revealed Maxwell–Wagner relaxation, while the J–E analysis indicated that Schottky emission dominates, with secondary space‐charge‐limited conduction occurring at high electric fields. The results demonstrate that oxygen‐vacancy and strain‐related defects serve as active transport mediators, providing a pathway to tune the electrical properties of ferrites for multifunctional electronic and energy applications.
Yadav et al. (Wed,) studied this question.