Due to their high specific Faraday rotation of up to several degrees per micrometer, single crystalline bismuth-substituted iron garnet films (RE-BIG) are used as compact magneto-optical elements in Faraday isolators and as optical sensor elements for the visualization of magnetic fields (magneto-optical image). The latter are capable of detecting local magnetic stray fields emanating from permanent magnets (NdFeB), polymer bonded magnets (magnetic encoders), domain materials (electrical sheets, shape memory alloys), media carriers (audio/video tapes), magnetic stripe cards (barcodes) and magnetic security features (inks).

Magneto-optical sensor films enable the rapid performance of a flat and non-destructive stray field test of magnetic materials in the field strength range from 0.05 to 500 mT with a lateral resolution of 1 to 30 micrometers. The big advantage is the direct contact of the sensor surface with the sample surface (near field testing). Thus the stray field propagation can be characterized with high spatial resolution regarding geometry, local field strength and polarity.
The targeted development of magneto-optical sensor films on the basis of bismuth-substituted iron garnet is the prerequisite for developing tailor-made system solutions for a wide range of measurement tasks and for setting up suitable magneto-optical measurement systems. Here INNOVENT can refer to a comprehensive expertise, which includes film growth as well as sensor fabrication and system development.