Synthesis, analysis, and characterizations to investigate the influence of ni dopant on the structural and magnetic properties of Co Fe 2 O4 nanoparticles confined within the mesoporous silica SBA-15 matrix

Abstract

This study designates the synthesis and characterization of undoped and Ni-doped CoFe2O4 nanoparticles within the highly ordered nanoscale channels of mesoporous silica SBA-15 matrix by using two-step nanocasting process. The impact of Ni doping in the structural and magnetic properties of CoFe2O4/SBA-15 nanocomposite was investigated by XRD, FT-IR, FESEM/EDX, N-2-adsorption/desorption, and VSM techniques. XRD studies have depicted that Ni doping results in pure ferrite phase with crystallite size decreasing from 11.8 to 10.2 nm and lattice constant's reduction due to smaller ionic radii of the nickel ions as against cobalt ions. The formation of metal-oxygen complexes located in the spinel lattice was proved by FT-IR spectroscopy which exhibits two main absorption bands belonging to the tetrahedral and octahedral sites. Compared with CoFe2O4/SBA-15, Ni0.5Co0.5Fe2O4/SBA-15 nanocomposite possesses higher BET surface area and pore volume due to creation of additional porosity in the mixed ferrite sample. The surface morphology of the CoFe2O4/SBA-15 and Ni0.5Co0.5Fe2O4/SBA-15 nanocomposites, as measured by FESEM, indicates the fiber-like aggregates consisting of relatively uniform short rod-shaped grains. Ni doping is observed to influence the ferromagnetic behavior significantly, while the saturation magnetization gets reduced from 18.12 to 12.74 emu/g which is associated with the lower orbital contribution to magnetic moment of Ni2+ ions in as against Co2+ ions, conversely, the coercivity gets increased from 158 to 249 Oe, which suggests the hardening of the magnetic material, which may be due to the increase in surface anisotropy resulted from the matrix effect. Therefore, the present study notifies the potential magneto-electronic applications of Ni0.5Co0.5Fe2O4/SBA-15 nanocomposite, with the realization of controllable size and magnetic properties along with SBA-15 matrix.