压电极化方向对磁电复合振子磁阻抗效应的影响

Influence of Piezoelectric Polarization Direction on the Magneto-Impedance Effect of Magnetoelectronic Composite Oscillator

本文研究了压电体分别沿长度和厚度极化的磁电复合振子的磁阻抗效应.根据压电体的极化理论,在洛伦兹模型和德拜模型基础上,利用磁电耦合理论研究了磁电复合振子有效相对介电常数与磁场的关系,数值模拟了有效相对介电常数随磁场的变化.由磁电复合振子的磁阻抗与有效相对介电常数的关系,理论分析了磁电复合振子在谐振频率下的磁阻抗效应.在理论分析基础上,实验研究了"三明治"结构磁电复合振子的磁阻抗效应.实验结果表明,在谐振频率下,磁场在0~50 mT范围内,当压电体的极化方向为长度极化时,其磁阻抗随磁场的变化率是压电体厚度极化的22倍,实验结果与理论模拟基本吻合.在此基础上,对实验结果的磁分辨率进行了计算,在谐振频率下,压电体长度极化磁电复合振子的磁分辨率为2.76×10^-12 T/μΩ,压电体厚度极化磁电复合振子的磁分辨率为78×10^-12 T/μΩ,本研究为地磁场的探测提供了理论基础.

In this paper,the magnetoimpedance effect of magnetoelectric composite oscillators with piezoelectric bodies polarized along their length and thickness is studied. Based on the polarization theory of piezoelectric body,i.e. Lorentz model and Debye model,the relationship between effective relative permittivity of the magnetoelectric composite oscillator and magnetic field is studied by using the magnetoelectric coupling theory. The variation of effective relative permittivity with magnetic field is simulated numerically. Based on the relationship between the magnetic impedance of the magnetoelectric composite oscillator and effective relative permittivity,the magnetoimpedance effect of the magnetoelectric composite oscillator at the resonant frequency is theoretically analyzed. The magnetic impedance effect of "sandwich"structure magnetoelectric composite oscillator is experimentally studied. The experimental results show that when the magnetic field in the range of 0~50 mT and at the resonant frequency,the polarization direction of the piezoelectric body is the length polarization,the change rate of the magneto-impedance with the magnetic field is 22 times that of the thickness polarization. The experimental results are basically consistent with the theoretical simulation. On this basis,magnetic resolution of the experimental results is calculated at the resonant frequency,the magnetic resolution of the piezoelectric body length polarization magnetoelectric composite oscillator is 2.76×10^-12 T/μΩ and the magnetic resolution of the piezoelectric body thickness polarized magnetoelectric composite oscillator is 78×10^-12 T/μΩ. This study provides a theoretical basis for the detection of geomagnetic fields.