Features of excitation and detection of magnetoacoustic emission in ferromagnetic objects

Abstract

We study how the conditions of excitation and detection influence the magnetoacoustic emission (MAE) parameters of ferromagnets. For a large group of metal ferromagnet samples differing in physical properties and dimensions, the dependence of the MAE amplitude on the frequency of the remagnetizing field has a similar nonmonotonic character. In all probed cases, the maximum of the amplitude corresponds to a field frequency of 3–5 Hz. The decrease in the MAE amplitude for a subsequent increase in the frequency of the alternating field is related to the action of eddy currents. It is shown that the size of the field corresponding to the MAE maximum, which for a given time dependence of the remagnetizing field can be determined by the time shift in an oscillogram, can be a new parameter of the structuroscopy of ferromagnets.