Bitter patterns in polarized light: A probe for microfields

This paper discusses the observation of Bitter patterns on YIG films made with a polarizing microscope. The local stray field associated with the domain structure induces a birefringence in the colloid which in turn determines the light intensity I transmitted by the analyzer. Under the conditions of fixed crossed polars, if the local field makes an angle ψ with the polarizer then I=k(1−cos 4ψ). The nature of the birefringence and its effect upon the intensity allows, in principle, a directional map of the stray field pattern to be constructed.