脉冲强磁场瞬态光学显微成像系统的研制与应用
发布时间：2019-01-18 17:51
【摘要】：近年来强磁场测量技术和其环境下的测量手段有了突飞猛进的发展,在强磁场下材料的电子能态、磁矩、微观结构等会发生一系列改变,产生形形色色的物理效应,从而能够对材料的不同物理机制进行研究。目前脉冲强磁场和稳态强磁场环境下的实验测量手段多种多样,主要有磁化测量、电输运测量、电极化测量、比热测量等等。其中稳态强磁场下的磁光显微成像通过利用光学显微镜成像的方法对样品表面的微观结构进行原位观察取得了许多突破性的进展,然而由于脉冲强磁场下的测量环境较为极端该显微成像的方法并未普及。近十年来随着高速成像技术、极低温技术以及脉冲磁体技术的成熟,使得脉冲强磁场下显微成像成为了可能,本文主要介绍了继日本脉冲强磁场磁光显微成像系统之后国内首个脉冲强磁场下的瞬态光学显微装置的研制过程,并利用该装置开展了一系列科学实验。论文主要内容如下： 一、简要介绍了强磁场实验技术的发展现状以及目前强磁场环境下的主要测量手段,其中强磁场下利用磁光显微成像的方法较常规方法能够直接观察到更多微观细节。然而由于脉冲场下的诸多极端环境该手段仍主要局限于稳态场,开发脉冲场下的磁光显微成像将能在提高最大磁场的同时大大减小相对稳态强磁场下磁光显微成像装置的成本以及对液氦的依赖性。 二、介绍了华中科技大学脉冲强磁场磁光克尔显微成像装置的研制过程,主要从脉冲电源、脉冲磁体、低温真空系统、成像采集以及信号测量这几个方面对系统结构以及原理进行了阐述。其中分别对磁场、低温进行了软件仿真和实验测试,并对磁光克尔成像原理和信号采集处理方法进行了介绍。 三、利用该装置对铁电材料CuFeO2进行了磁光克尔显微成像实验,观察了在极低温环境下CuFeO2样品表面磁畴的形貌以及磁场作用下克尔光强的变化。通过分析磁光克尔显微成像照片的光强得到了样品表面的磁化强度随磁场的变化,证实了在该磁光成像显微系统下利用克尔成像手段观察样品表面磁畴以及磁化趋势的可能性。 四、利用磁光显微成像系统对NiMn磁记忆合金温度驱动马氏体相变以及磁场驱动逆马氏体相变进行了细致的研究,首次通过显微镜原位观察的手段给出了Ni-Mn-Sn合金相变的不可逆过程的直接证据。并对NiMnInAl合金的马氏体磁驱动相变进行了对比,同样观察到了NiMnInAl合金在磁场驱动下马氏体相变的可逆过程。
[Abstract]:In recent years, the measurement technology of strong magnetic field and the measurement method under its environment have made rapid progress. In the strong magnetic field, a series of changes will take place in the electronic energy state, magnetic moment and microstructure of the material, which will produce various physical effects. It is possible to study different physical mechanisms of materials. At present, there are a variety of experimental methods in the environment of pulsed strong magnetic field and steady state strong magnetic field, such as magnetization measurement, electric transport measurement, electrode measurement, specific heat measurement and so on. Among them, the magneto-optical microimaging under the steady-state strong magnetic field has made many breakthrough progress by using the method of optical microscope imaging to observe the microstructure of the surface of the sample in situ. However, the method of microscopic imaging is not widely used because of the extreme measurement environment of pulsed strong magnetic field. With the development of high speed imaging technology, very low temperature technology and pulsed magnets technology, it is possible to make the microimaging under high pulse magnetic field possible in the last decade. This paper mainly introduces the development process of the first transient optical microscope device under high pulse magnetic field after the Japanese pulsed strong magnetic field magneto-optical microscopic imaging system. A series of scientific experiments have been carried out using the device. The main contents of this paper are as follows: 1. The development status of high magnetic field experimental technology and the main measurement methods under the environment of high magnetic field are briefly introduced. More microscopic details can be observed directly by using magneto-optical microscopic imaging under high magnetic field than by conventional methods. However, due to many extreme environments under the pulse field, the method is still mainly confined to the steady-state field. The development of magneto-optical microscopy imaging under pulsed field can increase the maximum magnetic field and reduce the cost of magneto-optical microscopy imaging device and its dependence on liquid helium compared with the steady-state strong magnetic field. Second, the development process of pulsed magnetic field magneto-optic Kerr microscopic imaging device in Huazhong University of Science and Technology is introduced, mainly from pulse power supply, pulse magnet, low temperature vacuum system, The structure and principle of the system are described in the aspects of imaging acquisition and signal measurement. The magnetic field and low temperature are simulated and tested by software, and the principle of magneto-optic Kerr imaging and the method of signal acquisition and processing are introduced. Thirdly, the magneto-optic Kerr microscopic imaging experiment of ferroelectric material CuFeO2 was carried out. The morphology of magnetic domain on the surface of CuFeO2 sample and the change of Kerr intensity under the action of magnetic field were observed at very low temperature. By analyzing the intensity of the magneto-optic Kerr microscopic images, the variation of the magnetization intensity with the magnetic field on the surface of the sample is obtained, and the possibility of observing the magnetic domain and the magnetization trend of the sample surface by using the Kerr imaging method under the magneto-optical imaging microscope system is confirmed. Fourthly, the temperature driven martensite transformation and the magnetic field driven inverse martensite transformation of NiMn magnetic memory alloy were studied by magneto-optical microscopy imaging system. For the first time, direct evidence of the irreversible process of phase transformation of Ni-Mn-Sn alloy was obtained by in situ microscope observation. The martensite magnetically driven transformation of NiMnInAl alloy was compared. The reversible process of martensite transformation in NiMnInAl alloy driven by magnetic field was also observed.
【学位授予单位】：华中科技大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TM936
本文编号：2410958
[Abstract]:In recent years, the measurement technology of strong magnetic field and the measurement method under its environment have made rapid progress. In the strong magnetic field, a series of changes will take place in the electronic energy state, magnetic moment and microstructure of the material, which will produce various physical effects. It is possible to study different physical mechanisms of materials. At present, there are a variety of experimental methods in the environment of pulsed strong magnetic field and steady state strong magnetic field, such as magnetization measurement, electric transport measurement, electrode measurement, specific heat measurement and so on. Among them, the magneto-optical microimaging under the steady-state strong magnetic field has made many breakthrough progress by using the method of optical microscope imaging to observe the microstructure of the surface of the sample in situ. However, the method of microscopic imaging is not widely used because of the extreme measurement environment of pulsed strong magnetic field. With the development of high speed imaging technology, very low temperature technology and pulsed magnets technology, it is possible to make the microimaging under high pulse magnetic field possible in the last decade. This paper mainly introduces the development process of the first transient optical microscope device under high pulse magnetic field after the Japanese pulsed strong magnetic field magneto-optical microscopic imaging system. A series of scientific experiments have been carried out using the device. The main contents of this paper are as follows: 1. The development status of high magnetic field experimental technology and the main measurement methods under the environment of high magnetic field are briefly introduced. More microscopic details can be observed directly by using magneto-optical microscopic imaging under high magnetic field than by conventional methods. However, due to many extreme environments under the pulse field, the method is still mainly confined to the steady-state field. The development of magneto-optical microscopy imaging under pulsed field can increase the maximum magnetic field and reduce the cost of magneto-optical microscopy imaging device and its dependence on liquid helium compared with the steady-state strong magnetic field. Second, the development process of pulsed magnetic field magneto-optic Kerr microscopic imaging device in Huazhong University of Science and Technology is introduced, mainly from pulse power supply, pulse magnet, low temperature vacuum system, The structure and principle of the system are described in the aspects of imaging acquisition and signal measurement. The magnetic field and low temperature are simulated and tested by software, and the principle of magneto-optic Kerr imaging and the method of signal acquisition and processing are introduced. Thirdly, the magneto-optic Kerr microscopic imaging experiment of ferroelectric material CuFeO2 was carried out. The morphology of magnetic domain on the surface of CuFeO2 sample and the change of Kerr intensity under the action of magnetic field were observed at very low temperature. By analyzing the intensity of the magneto-optic Kerr microscopic images, the variation of the magnetization intensity with the magnetic field on the surface of the sample is obtained, and the possibility of observing the magnetic domain and the magnetization trend of the sample surface by using the Kerr imaging method under the magneto-optical imaging microscope system is confirmed. Fourthly, the temperature driven martensite transformation and the magnetic field driven inverse martensite transformation of NiMn magnetic memory alloy were studied by magneto-optical microscopy imaging system. For the first time, direct evidence of the irreversible process of phase transformation of Ni-Mn-Sn alloy was obtained by in situ microscope observation. The martensite magnetically driven transformation of NiMnInAl alloy was compared. The reversible process of martensite transformation in NiMnInAl alloy driven by magnetic field was also observed.
【学位授予单位】：华中科技大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TM936
【共引文献】
相关期刊论文 前1条
1 郭志英;洪才浩;邢海英;唐坤;郑雷;徐伟;陈栋梁;崔明启;赵屹东;;A new soft X-ray magnetic circular dichroism facility at the BSRF beamline 4B7B[J];Chinese Physics C;2015年04期
相关博士学位论文 前1条
1 邓丽萍;Cu-Nb复合线材微观组织演变及力学和电学性能的研究[D];重庆大学;2014年
相关硕士学位论文 前5条
1 韦佳佳;Ni-Mn-In系列铁磁形状记忆合金的物性研究[D];山东大学;2013年
2 邹立颖;Cu-Nb金属基复合材料热变形本构关系的研究[D];东北大学;2012年
3 赵聪聪;强磁场下Cu-25%Ag合金的凝固及其大变形强化机制[D];东北大学;2012年
4 陈哲;基于新磁驱动机制的铁基磁控形状记忆合金设计研究[D];东北大学;2012年
5 陈家华;Ga2基Heusler合金的物性探索[D];北京化工大学;2014年
，本文编号：2410958
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