Impact of cation distribution in shaping the structural and magnetic characteristics of Ni-Cu ferrite

Abstract This study presents the synthesis, characterization and magnetic properties of of Cu 1−X Ni X Fe 2 O 4 nanocrystalline ferrites (0.0 ≤ × ≤ 1.0) using the sol–gel autocombustion method at a neutral pH. The samples were characterized by x-ray powder diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), vibrating sample magnetometry (VSM) and Mossbauer spectroscopy. The structural analysis confirmed the formation of mixed spinel structures, with crystallite sizes ranging from 22–32 nm. Mössbauer spectra of 57 Fe were recorded at room temperature (300 K) and liquid nitrogen temperature (77 K), and variations in line width, isomer shift, quadrupole splitting, and hyperfine magnetic field magnitudes were calculated for both tetrahedral and octahedral sublattices. The cation distribution, revealed through XRD, VSM and Mössbauer spectroscopy, shows a consistent pattern with nickel ions predominantly occupying octahedral sites. The magnetic properties were modified by substituting nickel ions with copper ions, affecting the distribution of magnetic Fe 3+ ions and the total magnetization. The maximum saturation magnetization and coercivity reached 59.54 emu g −1 and 327.8 Oe, respectively. These findings reveal a systematic modification of magnetic properties through nickel substitution, resulting in enhanced saturation magnetization and coercive force. Notably, the synthesized samples exhibit sufficiently high magnetic properties, making them suitable for practical applications such as magnetic hyperthermia, a promising therapeutic approach for cancer treatment. The nanoparticles can be designed to generate heat in response to an alternating magnetic field, allowing for targeted and controlled heating of tumor cells.