A study on the Faraday rotation of iron oxide ferrofluids synthesized at different pH values

Abstract

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 (Ms), Remanence (Mr) and Coercivity (Hc) 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.