A Study on the Faraday Rotation of Iron Oxide Ferrofluids Synthesized at Different pH Values

Chemical co-precipitation method was adopted to synthesize Fe3O4 nanoparticles at different pH values using oleic acid as surfactant. Structural investigation done using X-ray diffraction (XRD) technique reveals that the crystallite sizes calculated using Debye-Scherrer approximation increases with pH values. Surface morphology and chemical composition of the samples were investigated using Transmission electron microscope (TEM) and Energy dispersive analysis of X-rays (EDAX) analysis respectively. Room temperature magnetic measurements were done using vibrating sample magnetometer (VSM). Magnetic parameters of the sample such as Saturation magnetization (M-s), Remanence (M-r) and Coercivity (H-c) were found to enhance with increase in pH values. Verdet constant of the samples were calculated from Faraday rotation for various magnetic fields and it varies from 8.42 deg./Tcm to 11.88 deg./Tcm.