EXCITATION OF A RADIAL MODE VIBRATION IN A CONDUCTIVE FERRITE DISK DUE TO AN ALTERNATIVE CURRENT FLOWING THROUGH THE DISK

Deformations in conductive ferrite crystals due to electric currents flowing through them were reported previously (International J. Magnetism, vol. 6 pp. 135–141, 1974 and Proc. IEEE, vol. 62, pp. 140–141, 1974). Here we conclude that the deformations due to the currents are caused by the forces acting on magnetic dipoles in magnetic field-gradients which are formed by the currents’ flowing through conductive ferrite specimens. This phenomenon is a sort of magnetostriction and is efficient for exciting elastic vibrations, because the magnetic field due to the current is closed and has no free pole to form a demagnetization field. This method for excitation of vibrations will become a significant technique for mechanical filters, transducers, and the other magnetic devices, because the devices will be made, without wire winding, by printing and doping techniques which are ordinarily used for fabrications of semiconductor devices, and because electrical conductivities and magnetic properties of ferrites can be controlled by their chemical compositions and physical treatments. Copyright © 1979 by The Institute of Electrical and Electronics Engineers, Inc.