Impact of the Ni/Co ratio on structural and magnetic properties in A-site stoichiometric nanosized spinel ferrites

We present a meticulous synthesis of Co1-xNixFe2O4 nanoparticles (0.0 <= x <= 1.0) via the chemical citrate precursor technique. Comprehensive X-ray diffraction (XRD) analyses showcased prominent diffraction peaks, especially for the x = 0.0 sample, corroborating the impeccable cubic spinel ferrite structure devoid of extraneous phases. This structural integrity is further evidenced by a linear attenuation in unit cell parameters with heightened Ni2+ ion concentration, a phenomenon seamlessly aligning with Vegard's law and the nuances of the A-site ionic radii. Magnetic characterizations derived from Vibrating Sample Magnetometer (VSM) evaluations reveal a pronounced modulation in primary magnetic parameters with increasing Ni content. This modulation not only resonates with the charge and spin dynamics of the A-site ions but also accentuates the cardinal role of cation distribution between A- and B-sites in magnetic property determination.