Direct current imaging using a magneto-optical sensor

•The direct currents (DC) flux visualized by magneto-optical (MO) imaging method.•As indicator used Bi:YIG thin films prepared by the MOD method.•The minimum detectable magnetic field range of the MO sensor was about 0.2G.•MO imaging does not have any limitation on the sizes of the current flux. Magneto-optical (MO) imaging was implemented for the visualization of direct currents (DC) of patterned current wires using bismuth substituted yttrium iron garnet (Bi:YIG) sensor films prepared by the metal organic decomposition (MOD) method. The minimum detectable magnetic field range of the MO sensor was calculated to be about 0.2G. To enhance the contrast of DC images, in the image processing we have inverted the DC without changing the optical orientation between the analyzer and polarizer of the MO system. The measured magnetic field distributions of patterned current wires induced by a DC were in good agreement with results of COMSOL Multiphysics simulations.