The magnetic fluid is a novel kind of functional materials, with both magnetism and fluidity. It has numerous potential applications to sensors due to its unique features. This paper briefly reviews the progress of applications of magnetic fluids to sensors related to the volume, the flow rate, the angle, the temperature, the current and the magnetic field. Their sensing principles are analyzed. Based on the theory of the geometrical optics and the magnetically tunable refractive index of the magnetic fluid, theoretical derivations and numerical simulations of two kinds of magnetic field sensing systems are conduced, to promote sensor researches and applications based on the magnetic fluid.

nano-structured magnetic fluid  /  sensors  /  tunable refractive index