Superparamagnetic properties of nickel ferrite nanocrystals prepared by an organic-phase thermal decomposition

Nickel ferrite (NiFe2O4) was successfully synthesized via an optimized thermal decomposition method using appropriate acetylacetonate complexes. The synthesized powder was characterized by X-ray powder diffraction (XRPD), Fourier-transform infrared (FT-IR) spectroscopy, and transmission electron microscopy (TEM) analyses. The formation of a pure spinel phase was confirmed. According to TEM, NiFe2O4 particles were polygonal in shape with diameters of approximately 7.5 nm. The structural and morphological properties of the synthesized material aligned with its monocrystal nature, as evidenced by the consistency between crystal sizes obtained from XRPD and grain sizes acquired from TEM micrographs. The magnetic properties exhibited high sensitivity to external perturbations and experimental conditions, highlighting the selected synthetic pathway as the optimal choice for the preparation of monodisperse NiFe2O4 nanoparticles. The magnetization measurements revealed that the synthesized nanoparticles displayed superparamagnetic behavior under ambient conditions. These findings demonstrate the potential for prepared NiFe2O4 to be utilized in various applications that require highly sensitive magnetic behavior and suggest that the obtained nanoparticles can be highly exploited in the field of biomedicine.