Magneto-optical current sensor by domain wall motion in orthoferrites

A brief review of the latest developments on optical current measurements b ased on the Faraday effect is presented. In all existing magneto-optical cu rrent transformers, the main measured parameter is the polarization state o f the light transmitted by a sensor element. A new transformer is described by means of new results concerning the domain wall excitation. The measure d parameter is the geometrical position of the boundary between domains wit h opposite magnetizations, In a wide frequency band, including DC currents, the measurement results are a linear function of the measured current. The y are not affected by temperature changes and mechanical factors.