Piezoelectric-magnetic behavior of ferroelectrets coated with magnetic layer

Electrically charged porous electret films, reported as ferroelectrets or piezoelectrets, have drawn the attention of researchers due to their high piezoelectric activity, low density, and flexibility. This paper introduces a ferroelectret design for the development of piezoelectric-magnetic responses. Samples are prepared with an additional magnetic layer placed above open tubular channels made from fused electret films, and the piezoelectric direct effect of electrically charged samples is monitored. The results of the measurements show approximately 900 pC N-1 piezoelectric coefficients d(33). The piezoelectric-magnetic effect is an electrical response from a mechanical deformation caused by an external magnetic force. The magnetic field pulls the magnetic layer, mechanically deforming the electrically charged tubular structure, which creates a charge compensation to be measured as a charge density variation. A setup especially assembled for measuring the piezoelectric-magnetic response is described together with piezoelectric-magnetic values ranging from 94 up to 275 pC T-1.