Magneto-Optical Hysteresis Loops of Multidomain Materials

It has been made clear theoretically that Faraday loops which are often utilized for characterization in magnetic materials with multidomain differ from the magnetization curves when loops are traced with a single-ended fixed analyzer method as well as an extinction method. This is attributed to the light diffraction by the domains. The loops depend on the range of the diffracted beams allowed for the detection. When the detector accepts the entirety of the diffracted beams, the loop has the same shape as the magnetization curve. On the other hand, when only the zeroth-order beam is detected, the loop becomes deformed including a quadratic form of magnetization. However, such a loop deformation is completely eliminated by employing a dual-ended differential fixed analyzer method. It has been shown that the double-ended method is so excellent that loops whose shapes are equivalent to the magnetization curves can be traced even for materials with a large Faraday rotation.