A simple apparatus for the measurement of the Cotton-Mouton effect in particulate suspensions

An apparatus has been constructed for the practical realization of the Cotton-Mouton effect in colloidal suspensions. Measurements of the magnetically induced birefringence in such media, using a medium power argon-ion laser operating at a wavelength of 515 nm, have been made for variable magnetic field intensities up to 2.5 T. Data have been recorded on the four pure liquids-nitrobenzene, carbon disulphide, acetone, and benzene. The system has been primarily designed for studies on colloidal media for which the Cotton-Mouton effect can be large, thereby requiring relatively low intensity magnetic fields. Data for bentonite and vermiculite are reported, which demonstrate the ease and validity of such measurements for colloid characterization. These are the first known data on suspensions of vermiculite clay. Furthermore, the influence of any stray Faraday effect is examined.