Structural, mechanical, and magnetic properties of Co_0.6Sr_0.4Fe₂O₄ nanoparticles under heat treatment

Abstract In this study, we investigate the influence of annealing temperature on the structural, mechanical, and magnetic properties of Co 0.6 Sr 0.4 Fe 2 O 4 nanoparticles prepared using the coprecipitation method. The synthesized samples were characterized using several techniques, including transmission electron microscopy (TEM), x-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, and vibrating-sample magnetometry (VSM). SrCO 3 was formed with a Co 0.6 Sr 0.4 Fe 2 O 4 phase, and annealing resulted in the formation of secondary phases, including Fe 2 O 3 and hexagonal phases. All lattice parameters and bond lengths, obtained from the Rietveld analysis of the spinel ferrite phase, changed by annealing and were affected by forming impurity phases. Absorption bands and elastic properties were influenced by the annealing process. Transmission electron microscopy revealed the formation of semi-spherical and polygon-like nanoparticles that clustered into larger ones with increasing annealing temperature. TEM analysis showed a slight/negligible increase in the average particle size of NPs with increasing annealing temperature, averaging around 15 nm. The saturation magnetization, coercivity, and magnetic moment were influenced by the annealing process and the cation distribution of the spinel ferrite phase. The particle size distribution can control the switching field distribution (SFD) values.