Magnetic properties and noise in cylindrical Permalloy thin-film magnetometers

The magnetic properties and low-frequency noise measurements of thin films of Permalloy are described. The films are obtained by electrodeposition. They are polycrystalline and single domain. The noise due to the film is shown to be an increasing function of the dispersion angle α
90
. A model for the noise mechanism taking into account the magnetostatic stray field arising in the grain boundaries and the thermal agitation energy is given. It is in qualitative agreement with the experimental results.