Nonlinear magnetoelectric effects at high magnetic field amplitudes in composite multiferroics

作者：Fetisov L Y; Burdin D A; Ekonomov N A; Chashin D V; Zhang J; Srinivasan G; Fetisov Y K^*

来源：Journal of Physics D: Applied Physics , 2018, 51(15): 154003.

DOI：10.1088/1361-6463/aab384

• multiferroic
• magnetoelectric effect
• ferromagnetic
• ferroelectric
• magnetostriction
• piezoelectricity
• harmonics generation

Magnetoelectric effects (ME) in ferromagnetic-ferroelectric layered composites arise due to magnetostriction and piezoelectric effect in the ferroic phases and are mediated by mechanical strain. The ME coupling strength in such composites could be measured by electrical response to an applied ac magnetic field h and a bias magnetic field H. The coupling, in general, is linear for small ac field amplitudes, but one expects nonlinear ME interactions for high field strengths since the dependence of magnetostriction lambda on magnetic fields is nonlinear. Here we report on nonlinear voltage response of a composite of ferromagnetic Metglas and piezoelectric lanthanum gallium tantalate (langatate) subjected to an ac and a bias magnetic fields, resulting in the generation of voltages at harmonics of the frequency of h. The dependences of the ME voltage of the first four harmonics on the magnetic fields for H = 0-20 Oe and h = 0-50 Oe were measured. Up to a hundred harmonics were observed in the voltage versus frequency spectra and was indicative of high nonlinearity of the ME coupling in the multiferroic structure. It is shown that for h smaller than the saturation magnetic field H-S for magnetostriction in the ferromagnetic layer, the amplitudes of the ME voltages are proportional to the derivatives of lambda with respect to H and show a power-law dependence on the pumping field amplitude A(n)(H) similar to lambda((n))(H)h(n). We discuss a procedure for estimating the amplitudes of the harmonics for large pumping fields h, on the order of H-S. The nonlinear ME effects in the composites are of interest for application in signal processing devices and highly sensitive magnetic field sensors.

• 出版日期2018-4-18