Magneto-optical measurement of Barkhausen noise spectra

Magneto-optical techniques are increasingly employed for measurements of Barkhausen noise in ferromagnetic materials, especially for very thin films and microstructured samples, where the usual pickup coil or surface probe methods can be difficult to apply. Among the information that can be extracted from the Barkhausen signal, the noise power spectrum is of relevance because it gives important clues about the dynamics of the avalanches during the magnetization process. In this paper we propose a method for obtaining the Barkhausen noise spectra by means of magneto-optical Kerr effect measurements. We describe the experimental setup and the numerical elaboration of the signal, and we illustrate the advantages and the perspectives of this method.