Hydrothermal synthesis of NiFe2O4 nano-particles: structural, morphological, optical, electrical and magnetic properties

NiFe2O4 nano-crystallites with an average diameter of 8.9 nm are synthesized via hydrothermal method. The single-phase spinel structure is confirmed from X-ray diffractograms. Morphology is analysed by transmission and field emission scanning electron microscopes. High specific surface area of 55.7 m(2) g(-1) is obtained for nano-particles. The M- H loop and M- T curve behaviours are investigated by vibrating sample magnetometry. The optical band gap energy is estimated from the UV-visible spectrum. In addition, the frequency dependence of dielectric properties is investigated. Cole-Cole plots are drawn to study electrical conduction mechanism and the kind of relaxation-Debye or non-Debye type. Low a.c. conductivity and low magnetic losses are noticed at 5 MHz frequency, which are suitable for microwave device applications.