Adjustable ferrite amount for various characteristics of Ni _0.5 Cd _0.5 Fe ₂ O ₄ nanoparticles incorporated in a SiO ₂ matrix

ABSTRACT The (Ni 0.5 Cd 0.5 Fe 2 O 4 ) x (SiO 2 ) 100‒ x ( x = 0%‒100%) samples were synthesized through sol‒gel technique followed by the study of the evolution of crystalline phases at different temperatures. For the samples containing ferrite, the X‐ray diffraction indicated the development of ferrite and SiO 2 matrix and displayed single, low crystallized ferrite at low temperatures and well‐crystallized ferrite attended by Fe 2 O 3 and SiO 2 at high temperatures (1000°C). The crystallite size and lattice parameter increased with annealing temperature and the amount of ferrite incorporated in the SiO 2 matrix. The evolution of shape, size, and degree of agglomeration with the amount of ferrite incorporated in the SiO 2 matrix at 1000°C were investigated. The values of remanent and saturation magnetizations, anisotropy and coercivity, and the amount of ferrite incorporated in the SiO 2 matrix after annealing at 700°C and 1000°C were correlated with the particle morphology. The SiO 2 matrix exhibited diamagnetic behavior, while the Ni 0.5 Cd 0.5 Fe 2 O 4 incorporated in the SiO 2 matrix showed a superparamagnetic behavior. The amount of ferrite and annealing temperature impacts the particle sizes, which further affects the magnetic characteristics. The incorporation of Ni 0.5 Cd 0.5 Fe 2 O 4 nanoparticles into the inert SiO 2 matrix enabled the control of particle size, minimized particle agglomeration, and enhanced the magnetic properties.