Parametric Generation of Subharmonics in a Composite Multiferroic Resonator

Abstract

Parametric generation of subharmonics in a composite multiferroic resonator has been observed and investigated. The resonator has the form of a disk and contains two mechanically coupled layers, one of which is amorphous ferromagnet FeBSiC and the other piezoelectric lead zirconate-titanate. The resonator was placed inside two planar electromagnetic coils with orthogonal axes. A static magnetic field of 0-100 Oe was applied parallel to the plane of the resonator. The resonator was excited in the frequency range f = 9-10 kHz by either a harmonic magnetic field with an amplitude of up to 5 Oe generated by one of the coils, or a harmonic electric field with an amplitude of up to 500 V/cm applied to the piezoelectric layer. When the pump field was above a certain threshold, generation of a subharmonic of half-frequency (f/2) was observed for three different excitation methods. The first two employed either the direct magnetoelectric effect or the converse magnetoelectric effect, while in the third a transformer system was utilised. The subharmonic was generated in a limited range of pump frequencies and its amplitude was a nonlinear function of both the pump-field amplitude and the strength of static magnetic field. A theory of parametric generation of the subharmonic in a multiferroic resonator has been developed, taking into account the magnetoacoustic nonlinearity of the ferromagnetic layer of the structure and excitation of acoustic resonances near the pump and subharmonic frequencies. The theory qualitatively describes the main characteristics of the subharmonic generation.

Магнитоэлектрические Устройства Электроники И Информатики На Основе Мультиферроидных Гетероструктур

“…Разработаны принципы создания устройств преобразования частоты радиосигналов, использующих нелинейные МЭ-эффекты в мультиферроидных гетероструктурах. Нелинейность МЭ-эффектов возникает из-за нелинейной зависимости магнитострикции ФМ-слоя от магнитного поля H [11] и приводит к генерации гармоник, комбинационных частот и субгармоник на частотах возбуждающего поля [12]. Конструкция МЭ удвоителя частоты схематически показана на рис.…”

Noise generation in a bilayer ferromagnet-piezoelectric heterostructure at the converse magnetoelectric effect

“…The origins of nonlinearity are the nonlinear dependence of the magnetostriction λ(H) and the magnetization M(H) of the FM layer on the dc magnetic field H, the nonlinear dependence of the polarization P(E) and deformation S(E) of the PE layer on the electric field E, as well as the nonlinear dependence of the elastic moduli of the layers on the magnetic and electric fields and mechanical stress [18][19][20]. Among the detected nonlinear ME effects, are the generation of harmonics [21,22] and sub-harmonics [23] of voltage or magnetization, generation of voltage or magnetization with the sum and difference frequencies when the structure is excited by two magnetic or electric ac fields [24,25], frequency mixing upon excitation of structures by electric and magnetic fields simultaneously [26], the onset of bistability in an ME resonator [27], excitation of acoustic oscillations under the action of magnetic field pulses [28], parametric amplification of oscillations upon excitation of heterostructures by an electric field [29], the nonlinear transformation of the magnetic noise spectrum in an ME heterostructure [30].…”