Abstract: A polarization microscope optically detects the effect of the magnetic field from a sub-optical resolution magnetic structure on a magneto-optical transducer. The magneto-optical transducer includes a magnetic layer with a magnetization that is changed by the magnetic field produced by the magnetic structure. The saturation field of the magnetic layer is sufficiently lower than the magnetic field produced by the magnetic structure that the area of magnetization change in the magnetic layer is optically resolvable by the polarization microscope. A probe may be used to provide a current to the sample to produce the magnetic field. By analyzing the optically detected magnetization, one or more characteristics of the sample may be determined. A magnetic recording storage layer may be deposited over the magnetic layer, where a magnetic field produced by the sample is written to the magnetic recording storage layer to effect the magnetization of the magnetic layer.

Abstract: A magnetic field generator that is formed from a magnetic thin film, e.g., of ferrimagnetic garnet with a two magnetic domains with a domain wall between the two magnetic domains, is provided. A localized magnetic field is produced by the domain wall and is used as a magnetic field source for a sample held on or near the surface of the magnetic thin film. The sample response to the magnetic field is measured for one or more positions of the domain wall with respect to the sample. From the measured response, a desired parameter may be determined and stored. The position of the domain wall may be oscillated at high frequency to produce a voltage signal in the inductive sample. Alternatively, distortions in the domain wall may be imaged and used to identify or characterize structures in the sample.