Evidence of birefringence due to two phases in the magnetic fluid film

H. E. Horng¹ - S. Y. Yang¹ - S. L. Lee¹ - J. M. Wu² - J. T. Jeng¹ - Chin-Yih Hong³ - H. C. Yang²

¹ Department of Physics, National Taiwan Normal University, Taipei 117, Taiwan
² Department of Physics, National Taiwan University, Taipei 106, Taiwan
³ Department of Mechanical Engineering, Da-Yeh University, Chang-Hwa 515, Taiwan

Abstract
The angle Dh made by the principal axis of the transmitted elliptical polarization with respect to the incident linear polarization was measured to study the birefringence effect of a magnetic fluid film under a magnetic field H parallel to the plane of the film. When varying the angle q span by H with respect to the incident linear polarization, the Dh was found to be a symmetric function of q with a relative maximum at q around 45o. This Dh-q relation was found for the first time and a theoretical two-phase model is developed to clarify the mechanism of the birefringence effect of ferrofluids. Table 1, Figs 5, Refs 15.