Superparamagnetic cobalt-substituted copper zinc ferrialuminate: synthesis, morphological, magnetic and dielectric properties investigation

Abstract

The cobalt-substituted copper zinc ferrite (Cu0.3Zn0.7−xCoxFeAlO4, CZC ferrite) was chemically synthesized by the sol−gel methodology. The phase identification, crystal structure change confirmation, morphology analysis, and magnetic evolution of samples have been studied. The X-ray diffraction and vibrating sample magnetometer (VSM) were used for structural and magnetic studies of the prepared CZC ferrite samples. The cation distribution carried out from X-ray analysis confirms the occupancy of Fe3+, Zn2+ and Cu2+ on tetrahedral sites and Fe3+, Cu2+, Al3+ and Co2+ on octahedral sites in the crystal lattice. The spherical-shaped nanoparticles of 22−32 nm were observed from TEM images, and the nanocrystallinity of particles was confirmed from HRTEM. Hysteresis curves of the CZC demonstrate modifications in coercivity, magnetization and magnetic remanence with Co2+ ions doping in CZC systems. All the samples show soft magnetic behavior. For x = 0.3, lower values of Hc and Mr indicate super-paramagnetic nature. The dielectric behavior of CZC system was analyzed with frequency variation of real and imaginary portion of dielectric constant. The effects of multi-elementals like Cu, Zn, Co, and Al on ferrite are studied in this paper. The transition of ferrite from ferrimagnetic to superparamagnetic is observed in this study.