Study of magneto-optic effect on Mn_1-xZn_xFe₂O₄ nanoferrofluids

Mn_1-xZn_xFe₂O₄ nanoparticles (with x varying as 0.1, 0.3, 0.5, 0.7 and 0.9) have been synthesized by co- precipitation method using polyvinyl alcohol as surfactant. Structural analysis and surface morphology of the samples were analysed using X-ray diffraction and scanning electron microscope respectively. The Scherer approximation was used to obtain crystallite sizes and found to decrease from 8.9 nm to 4.3 nm with increase in zinc substitution. The chemical composition of samples obtained through EDAX was comparable with the initial substitutions. Saturation magnetization (M_s), Remanence (M_r) and Coercivity (H_c) were measured using VSM at room temperature and found to decrease with increase in zinc substitution. Verdet constant of the samples are obtained from Faraday rotation for various magnetic fields and it varies from 18 × 10⁻⁴ to 3 × 10⁻⁴deg/Gcm with zinc substitution.