Research On Self-biased Magnetoelectric Laminate Composites And Magnetic Sensing Characteristics

As one of the three pillars of modern information science, sensing technology is the technical foundation of information system's survival and development. As a kind of important way to get the modern information, magnetic sensing technology has been widely used in industry, military, life science, space exploration, smart grid and other fields. At present, magnetic sensors develop in the direction of high sensitivity, high resolution, miniaturization and low cost, the traditional magnetic sensors can not satisfy and adapt to the complex work environment and measurement requirements, researching on the new magnetic sensing technology has important academic significance and wide application prospects.Magnetoelectric materials can realize passive measurement, has wide bandwidth, high sensitivity and good linearity, showing good development potential in the field of magnetic sensors. Magnetoelectric composites have excellent properties at room temperature, and the preparation process is simple, which is an ideal device to detect the weak magnetic field. Currently, using magnetoelectric composites to detect magnetic fields was still in the stage of research, financially supported by the National Natural Science Foundation of China(No. 51475061), this thesis sets magnetoelectric laminated composite materials as the research object, theoretically and experimentally investigates magnetoelectric composite materials under zero biased magnetic field and their magnetic sensing applications. The main works of this thesis are summarized as follows:(1)The magnetoelectric effect with different materials, different work modes and different composite modes of magnetostrictive/piezoelectric laminated materials are researched, the output characteristics of magnetoelectric laminated materials at low frequency and resonant frequency is analyzed, we confirm the factors that affect the magnetic sensor sensitivity of magnetoelectric laminated materials, it provide the theoretical basis to design high performance self-biased magnetoelectric laminated materials.(2)For traditional magnetostrictive materials, their performance is vulnerable to the bias magnetic field, we proposed a new type of composite magnetostrictive material which composed by soft magnetic alloy and giant magnetostrictive material with big magnetic differences. Two kinds of magnetic materials can effectively enhance the internal magnetic field in the magnetostrictive materials, thus improve the performance of materials under zero biased magnetic field. The physical mechanism of self-biased phenomenon is revealed, theoretical derivation and simulation software are used to study the effective internal magnetic field of magnetostrictive materials.(3)Using the composite magnetostrictive materials and piezoelectric materials, we design a five phase symmetrical self-biased magnetoelectric laminated material, experimentally studied the magnetoelectric conversion performance of magnetoelectric laminated material without biased magnetic field at the low frequency and resonant frequency, the results show that compared with the traditional magnetoelectric composite materials, the proposed composite materials has more excellent performance under zero-biased magnetic field, and the thickness of soft magnetic alloy, excitation frequency, etc can affect the magnetoelectric properties of composite materials.(4)Symmetrical self-biased magnetoelectric laminated material can be used to design a kind of self-biased magnetic field sensor, this sensor can detect weak alternating magnetic field, thus we build the magnetic sensor test system to study the sensing performance of self-biased magnetic field sensor. Meanwhile, the sensor can be applied to detect the power transmission line, and realize effective monitor of the power supply line.