Electromagnetic excitation of sound in iron borate

Abstract

The observation of linear electromagnetic generation of sound of longitudinal (at a frequency of ∼230MHz) and transverse (∼180MHz) polarization in an iron borate slab is reported. The sound is excited by a magnetic field h∼ with an amplitude of up to 1Oe and a direction parallel to the (111) basal plane of the slab. The linear generation of sound of longitudinal polarization is observed for the first time. The inverse effect—generation of a field h∼ by sound relayed into the iron borate from an external source—is also observed. The field dependence of the signal in an external bias field H lying in the basal plane of the sample is also investigated. A piezomagnetic mechanism of excitation of longitudinal sound by a Bloch domain wall is discussed qualitatively.