Magneto optic imaging: normal and parallel field components of in-plane magnetized sample,

5. H. FERRARI, M. THIBAULT, V. BEKERIS, T.H. JOHANSEN

JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS

Elsevier

Año: 2007 vol. 313 p. 98 - 106

0304-8853

  Magneto-optical (MO) imaging has become a powerful tool for determining magnetic properties of materials by detecting the stray magnetic fields . The technique consists in measuring the Faraday rotation in the light polarization plane when light travels through a sensitive garnet (Ferrite garnet film FGF) placed in close contact to the simple. For in plane magnetized simples the MO image is not trivially related to the simple magnetization, and to contribute to this understanding we have imaged commercial audio tapes in which computer generated functions were recorded. We present MO images of periodically in-plane magnetized tapes with square, sawtooth, triangular and sinusoidal waveforms, for which we analytically calculate the perpendicular stray magnetic field component generated by the tape. As a first approach we correlate the measured light intensity with the perpendicular field component at the FGF, and we show that it can be approximated to the gradient of the sample magnetization.