Qualitative explanation for the Schäfer-Hubert effect: A boundary effect at the crossroads of magneto-optics and near-field optics

I present a simple theoretical interpretation of an anomalous magneto-optical effect at the domain boundary. This effect was discovered by Schäfer and Hubert Phys. Status Solidi A 118 271 (1990)] but was not supported by a clear physical explanation. From a familiar dielectric law, I derive the boundary magneto-optical effect concurrently with the bulk magneto-optical effect, i.e., the Faraday-Kerr effect. This boundary effect originates in the boundary charge density and is identified as the Schäfer-Hubert effect, based on a comparison of my theory and experimental results. Furthermore, I demonstrate that the Schäfer-Hubert effect predominates over the Faraday-Kerr effect and will be observed in the near field of a system with small-scale domains.