Transient Optical Phenomenon in Ferrofluids

In this paper, we report the experimental observation of diffraction patterns in a ferrofluid comprising of Fe3O4 nanoparticles in hexane by a 10 mW He-Ne laser beam. An external dc magnetic field (∼1.7 kG) was applied perpendicular to the beam. Transient phenomenon in diffraction patterns is studied with and without magnetic field. Diffraction patterns showed a variation in both zero and applied magnetic field. This provides some information of non-linear optical properties and magneto-optical effects. Laser beam passed through a sample establishes refractive index gradient modifying the original Gaussian beam of the laser. Analysis of transient diffraction patterns can be used to study the parameters of ferrofluid like viscosity and thermal conductivity. This gives a new insight to understand the dynamics of the magnetic fluid and its potential use for the development of ferrofluid based sensors.