Magneto-optic measurements on uneven magnetic layers on cardboard

Measurements of magnetic hysteresis loops by magneto-optic Kerr effect (MOKE) are usually performed on even surfaces which reflect the impinging laser beam without any disturbance. Alternatively, such measurements can be done on regularly structured samples, resulting in the possibility to investigate different diffraction orders who deliver different information about the magnetism in the magnetic particles. Rough magnetic surfaces, however, occur when rough substrates are coated with a magnetic layer, or when large magnetic particles are placed on a base material due to practical reasons. The article depicts the possibility to measure magnetic hysteresis loops on surfaces with a roughness about one order of magnitude higher than the light wavelength. This enables applied measurements of magnetic parameters on biological samples, textiles, irregular magnetic nanofibers etc.