Nonlinear magnetoelectric effect in multiferroic nanostructure TbCo/FeCo-AlN in high frequencyelectromagnetic field

Archive ouverte : Poster de conférence

Ignatov, Yury | Klimov, Alexey | Tiercelin, Nicolas | Preobrazhensky, Vladimir L. | Talbi, Abdelkrim | Pernod, Philippe | Nikitov, Sergey

Edité par HAL CCSD

International audience. Uniaxial TbCo/FeCo thin film intermetallic nanostructures are of interest because of their giant magnetostriction and uniaxial magnetic anisotropy that allows inducing of spin reorientation transition (SRT) by application of external magnetic field. It was shown that magnetoelectric effect can be appreciably enhanced in a composite structure near SRT [1]. High-frequency (HF) demodulation accompanied by resonant excitation of elastic vibrations was previously observed near SRT in nanostructured TbCo/FeCo giant magnetistrictive film deposited on Si substrate [2]. One can expect that the usage of ferromagnetic resonance (FMR), SRT, acoustic resonance, giant magnetostriction and a significant value of piezoelectric coefficientjointly enhance nonlinear magnetoelectric conversion in thin film structures.In the present work we report on the nonlinear resonance magnetoelectric effect induced by HF electromagnetic field in thin film composite multiferroic structure. The effect is studied in conditions of spin reorientation transition in magnetostrictive nanostructure. The results of calculations are in good agreement with the experimental data on magnetic field dependence of low-frequency (LF) magnetoelectric voltage and on HF power absorption. It is shown that conductivity contribution to FMR line width is relatively weak in magnetostrictive nanostructure. Observed unusual disappearing of the FMR line in the saturation phase, where magnetization is collinear to magnetizing field, is explained by specific geometry of the experiment and strong HF absorption. Obtained value of nonlinear magnetoelectric conversion coefficient amounts to 100 µV/mW. Calculations show for optimal orientation of anisotropy axis to the external alternating magnetic field direction increase the conversion coefficient one order of value.

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