层状磁电复合材料谐振频率下的巨磁电容效应

对三明治复合结构Tb_xDy_1-xFe_2-y/Pb(Zr, Ti)O₃/Tb_xDy_1-xFe_2-y的电容与频率及磁场的函数关系进行了实验和理论研究. 实验发现,该复合材料样品的电容随频率的增加而出现多个谐振峰,并且其谐振点随磁场的增加而发生频移. 在谐振点附近,观察到样品的阻抗随磁场的增加由容抗性转变为感抗性,从而同时观察到巨大的正磁电容效应和负磁电容效应. 由复合材料的弹性力学本构方程出发,对该类样品的电容随频率及磁场的变化进行了理论模拟. 结果显示,模拟曲线与实验结果符合得很好. 理论表明该磁致伸缩/压电复合材料的磁电容效应源于磁场诱变的铁磁相柔顺系数. 关键词： 层状复合材料 界面弹性耦合 磁电容效应

Magnetocapacitance effect of magnetoelectric laminated composite at resonant frequency

A sandwich-like laminated composite of Tb_xDy_1-xFe_2-y/Pb(Zr, Ti)O₃/Tb_xDy_1-xFe_2-y is prepared with a bonding method. The experimental study shows that the capacitance of the sample has several resonant peaks in the range of the frequency manipulated, and the resonant points shifte with the increase of applied magnetic field. The impedance of the sample also varies from capacitive to inductive ones at about the resonant point by changing the magnetic field. Giant positive and negative magnetocapacitance effects are observed simultaneously near the resonant frequency. From the constitutive equations of magnet and piezoelectrics involved, the capacitances as functions of frequency and magnetic field were theoretically modeled respectively. The results show that the experimental results are in good agreement with the theoretical ones, suggesting that the magnetocapacitance effect of the layered composite of magnetostriction/ piezoelectric originates from the magnetic field-controlled compliance coefficient of the ferromagnetic phase in the sample.