伸缩-剪切模式自偏置铌酸锂基复合材料的磁电性能和高频谐振响应

Magnetoelectric effect in stretch-shear mode self-biased LiNbO_3 based composite with high-frequency resonant response

选用多种切型铌酸锂(LiNbO_3)单晶,研究了铁基非晶合金(Metglas)/LiNbO_3叠层复合材料基于伸缩-剪切模式的磁电耦合性能,揭示了铌酸锂单晶压电系数与复合材料剪切磁电耦合系数的对应关系,在使用铌酸锂xzt/30~?切型时得到了最优化剪切磁电系数.通过SrFe12O19薄磁带提供偏置磁场,Metglas/LiNbO_3磁电复合材料可在没有外加直流磁场时实现剪切磁电响应,并在0.991 MHz和3.51 MHz频率时分别测出了谐振磁电系数,有望将铌酸锂基剪切磁电复合材料用于高频磁场探测.

Magnetoelectric（ME） composites have received attention abidingly due to the promising potential applications in magnetic field sensor and energy harvester. In recent years, shear mode ME composite was frequently discussed with promising applications in high-frequency magnetic field with large signal-to-noise ratio. Single-crystal LiNbO3, as a leadfree piezoelectric phase with high mechanical quality factor and small dielectric constant, is suitable for achieving a large shear ME effect with large shear piezoelectric coefficient d（15） or d（24）, and different piezoelectric coefficients can be obtained by crystal-cut transformation. The transformation rule of shear ME coefficient with transformation of LiNbO3 crystal orientation and the MHz high-frequency magnetic detection is still lacking. Furthermore, self-biased ME composite can be obtained with SrFe（12）O（19） ribbon, which is useful for the integration and miniaturization of ME sensor. In the present work, we use a series of X-cut LiNbO3 to obtain different d（15） or d（16） in a stretch-shear ME composite. Piezoelectric coefficient d（15） and ME coefficient α（E15） of Metglas/LiNbO3 composite are obtained in experiment, respectively. The results show that LiNbO3 xzt/30-？has the largest d（15） and α（E15）, and the transformation rule of α（E15） is consistent with the coordinate transformation of d（15）. The structure of stretch-shear ME composite is optimized to improve the ME coefficient. Then the stretch-shear mode self-biased SrFe（12）O（19）/Metglas/LiNbO3 composite is fabricated, and shear ME response is observed under zero external direct current magnetic bias. Moreover, α（E15） at electromechanical resonance frequency is gained at shear-mode high frequency（0.991 MHz and 3.51 MHz）. The largest ME coefficient α（E15） is acquired in the stretch-shear 5-foil Metglas/LiNbO3（xzt/30-？） composite of 134.16 mV/（cm·Oe） at 1 kHz and 9.17 V/（cm·Oe）at 3.51 MHz. This work is beneficial to the confirming of the corresponding rules of shear ME coefficient and LiNbO3 piezoelectric coefficient, showing that the composite possesses the potential applications in integration, miniaturization and high-frequency resonant sensor.