Basic Research And Application Of CoMg_xZr_yFe_2-x-yO₄/PZT Magnetoelectric Composites

With the advent of the information age,the Internet of Things technology has attracted more and more attention.As one of the important carriers in its application,magnetic sensors have drawn the attention of many scientific researchers.The sensitivity of a magnetic sensor is a key indicator that determines its application value and scope,and is mainly determined by the intrinsic parameters of the magnetic materials.Among the magnetic materials,the magnetoelectric composite material has been used as the magneto-sensitive element of the magnetic sensor due to its favorable magnetoelectric coupling characteristics.This paper mainly studied the magnetostrictive material with good piezomagnetic coefficient and its composite method with PZT piezoelectric ceramics,and designed the magneto-sensitive element based on the obtained magnetoelectric composite material to realize its application in low magnetic field.First,this paper investigated the microstructure,magnetic properties and piezomagnetic coefficient of the material after Mg²⁺substitution and Mg²⁺-Zr⁴⁺synergistic substitution of Fe³⁺in CoFe₂O₄.The results showed that appropriate amount of Mg²⁺substitution and Mg²⁺-Zr⁴⁺synergistic substitution can effectively promote the grain growth of CoFe₂O₄,but increase the porosity as well as reduce the saturation magnetization.In the low magnetic field,Mg²⁺substitution improved the piezomagnetic coefficient of cobalt ferrite;however,it also lowered the magnetostriction coefficient of cobalt ferrite.The Mg²⁺-Zr⁴⁺synergistic substitution slightly reduced the magnetostriction coefficient of the material,but further enhanced the piezomagnetic coefficient of the material in the low magnetic field.When the content of Mg²⁺was 0.05and Zr⁴⁺was 0.02,the piezomagnetic coefficient reached 4.3×10^-9m/A.With CoMg_0.05Zr_0.02Fe_1.93O₄ as the magnetostrictive component,PZT piezoelectric ceramic with good piezoelectric properties as piezoelectric component,the influence of the PZT mass ratio or thickness ratio on the magnetoelectric properties of the particle-inclusion and layered composite magnetoelectric composite materials were studied.Comparing these two types of composite materials,it was found that as the mass ratio of PZT increased,the magnetic properties of the material of particle inclusion type decreased,but the dielectric properties increased;as for the layered composite materials,when the thickness of PZT increased,the magnetoelectric conversion coefficient increased,and the maximum value of the magnetoelectric conversion coefficient(145m Vcm^-1Oe^-1)appeared in the magnetic field below 60Oe,indicating that the magnetoelectric conversion coefficient of the composite material in the low magnetic field was effectively improved.Finally,the comsol software was used to simulate and design the magnetic sensor.The simulation of the magnetic sensor was performed based on a model with a length of20mm and a width of 3mm,and the thickness as variable.It was found that the maximum elastic strain energy gradually increased with the increase of thickness,which was consistent with the experimental results.The model was optimized,and a heterogeneous sintered layered magnetoelectric composite material was prepared based on the LTCC(low temperature co-fired ceramic)process,and the magnetoelectric conversion coefficient was increased to 152m Vcm^-1Oe^-1.