Mössbauer, Magnetization and Structure Characterizations of the Annealed Sr_1/3Mn_1/3Co_1/3Fe₂O₄ Ferrite Nanoparticles

Sr_1/3Mn_1/3Co_1/3Fe₂O₄ ferrite nanoparticles were synthesized by glycol thermal technique. The structure and morphology of the Nano ferrites were studied by X-ray powder diffraction, Fourier transform infrared FTIR, high-resolution scanning electron microscopy, and high-resolution transmission electron microscopy. The induced internal strains were investigated by Williamson plots. The results show mono-dispersive property of the sample and particle sizes that increase with increasing annealing temperature, T_A. The magnetic hyperfine fields were found to be sensitive to T_A as seen from room temperature ⁵⁷Fe Mössbauer measurements. The magnetic hysteresis loops were performed in external magnetic field of up to 50 kOe. Room temperature M − H loops showed that the coercive fields increased to a maximum at T_A of 500 °C and then decreased thereafter. Significant increases in coercive fields were observed at a measuring temperature of 4 K. Distortions in the hysteresis loops at 4 K were observed where thermal annealing effect appears to induce strong linear correlation between coercive fields and saturation magnetizations.