Structural Evolution and Zn Induced Lattice Modification in Indium Stabilized Cobalt Ferrite Nanoparticles

Co1-xZnxFe1.92In0.08O4 ferrite nanoparticles with x = 0.0, 0.25, 0.50, 0.75, and 1.0 were synthesized using the sol–gel auto-combustion method followed by annealing at 800 °C. The structural evolution induced by Zn substitution was systematically investigated using X-ray diffraction. All compositions crystallize in a single-phase cubic spinel structure, confirming successful incorporation of Zn into the cobalt ferrite lattice. A progressive increase in lattice parameter with Zn content is observed, indicating homogeneous substitution and Vegard-type solid-solution behavior. The corresponding variation in unit cell volume and X-ray density further supports Zn-induced lattice expansion without structural instability. To elucidate local and extended structural modifications, XRD-derived allied parameters, including cation–oxygen bond lengths, polyhedral geometry, and cation hopping distances, were evaluated. These parameters exhibit consistent compositional trends, demonstrating cooperative expansion of both tetrahedral and octahedral sublattices. The results confirm that Zn substitution leads to uniform lattice dilation while preserving the structural integrity of the indium-stabilized spinel framework. This comprehensive structural analysis provides a reliable basis for understanding composition-driven lattice modification in Zn-substituted cobalt ferrite nanoparticles.