The Design And Application Of Magnetoelectric Effect Measurement System Based On Pulsed High Magnetic Field

With the development of technology, the characteristic of miniaturization and integration of devices demands new materials. Multifunctional materials, especially magnetoelectric materials, have been drawing considerable attentions. However, the magnetoelectric coupling effect of single-phase magnetoelectric materials is very weak. Taditional methods are difficult to obtain effective signal, which seriously affects the developments of the study on the magnetoelectric effect and their physics. As the extreme experimental conditions, high magnetic field and cryogenicscould change the electronic structure via the interaction with charge and spin, so they could be used to control the physical properties of the material, and could be applied to reveal the microscopic mechanism of the material. Traditional measuring techniques of magnetoelectric materials are not suitable for the high magnetic field and extrme low temperature. In this paper, based on the pulse magnetic field and low temperature environment, we design a magnetoelectric effect measuring system. In order to test the perfomance of the designed system, the magnetoelectric effect of CuFeO2single crystal is measured. The main contents of the thesis are as follows:First, the background and the development of pulse magnetic field are introduced. The relationship and difference between magnetoelectric materials and multiferroic materials are described. Some of magnetoelectric coupling mechanisms are elaborated. The current research statuses of single-phase and composite magnetoelectric materials are also discussed. Then, we introduce some methods of measuring the magnetoelectric effect and summarize their advantages and disadvantages. Based on the traditional magnetoelectric effect measuring method, we design a newly measuring system which is applied in the environment of pulsed high magnetic field and extreme low temperature.Second, we have designed a magnetoelectric effect measurement system based on pulsed magnetic field, extremely low temperature and electric field. The theoretical analysis and experimental verification are set up to optimize the hardware system. The system has realized the measurement of magnetoelectric coupling under a pulsed high magnetic field (magnetic field up to60T) and wide temperature range (2-300K). Compared with traditional measurement system of magnetoelectric coupling, this designed system has high magnetic field intensity, strong polarization current signal, so it is easier to measure magnetoelectic signal. Meanwhile, as the high change rate of the magnetic field, the system could also be used to study the dynamic behavior of the magnetic coupling.Third, based on the characteristics of pulse high magnetic field and measurement hardware, we design the software of the magnetoelectric effect measurement system using LabVIEW programming. The software realizes remote control, measurement and the data automatic processing. In order to improve the efficiency of data processing, we have designed the data processing software of the magnetoelectric effect measurement system.Fourth, according to the theoretical analysis and testing of the various components of the system, the experimental verification of the magnetoelectric effect measurement system is set up using CuFeO2single crystal. The magnetoelectric effect measurement system is used to study magnetoelectric coupling behavior in the CuFeO2single crystal. Pulsed high magnetic fields with various magnetic field sweep rates and magnitudes are used to investigate the dynamic behavior of the magnetoelectric effects in CuFeO2under different temperatures. The experimental results show that the reliability and high precision of the system have achieved and the system can satisify the requirement of the magnetoelectric effect research.