Synthesis and magnetic studies of Ni-Zn ferrite nanoparticles

Ni-Zn ferrite nanoparticles of the system, Ni-0.65 Zn-0.35 Fe-2 O-4, were synthesized by a soft chemical approach of co-precipitation method. These nanoparticles were separated into four batches and they were annealed at different temperatures from 200 to 800 degrees C for improved crystallization. All the samples were then characterized by X-ray diffraction, vibrating sample magnetometer and ferromagnetic resonance spectrometer techniques. The XRD patterns confirm spinel structures while the particle sizes, ranging from 9.9 to 15.7 nm, increase with the increase in heat treating temperature. The magnetization values are extremely small even at 10 kOe fields with vanished hysteresis at lower heat treating temperatures; thus leading close to the superparamagnetic nature. The resonance parameters deduced from the FMR spectra are in support of the magnetisation data.