Relaxation behavior measuring of transmitted light through ferrofluids film

Abstract

In this paper, relaxation behavior of transmitted light through thin ferrofluid film under an applied magnetic field is measured. The results show that the intensity of transmitted light through a ferrofluid film increases quickly as soon as an external magnetic field is applied then weakens with time. If uniformity of the field is poor, the transmission of light continuously decreases in a measured duration. Otherwise, the transmission of light will tend increasingly towards a stable value after it decreases to a minimum value while the gradient of the field is low. The relaxation time would increase to an order of some hundreds seconds magnitude and is dependent on the strength of magnetic field and viscosity of the ferrofluids. The field-induced relaxation behaviors of transmitted light through ferrofluids correspond to anisotropic microstructure of the ferrofluids under applied magnetic field.