多铁异质结中电场调控磁性的研究

发布时间：2018-01-05 10:26

本文关键词：多铁异质结中电场调控磁性的研究　出处：《山东大学》2017年硕士论文　论文类型：学位论文

【摘要】：伴随着第三次科技革命的发生以及现代科学技术的迅猛发展,多铁性材料应用于高性能磁性器件显现出尺寸小、速度快、精度高等特点,从而广泛地用于当代通信技术、信息存储系统、电磁干扰技术等领域。多铁性材料是具有两种或以上铁性质,例如铁电性,铁磁性和铁弹性,并且重要的是理解并能够在磁电效应方面操纵多铁性材料的磁性。由于磁电耦合(ME)效应的快速,低功率的工作方式,多铁性材料系统通常用于制造传感器、多状态存储器和其它自旋电子器件。对于应用于微波频段的磁性薄膜材料,磁性材料的电磁参数和复数磁导率的表征成为研究的主要的内容同时具有相当重要的意义。本文主要研究了单层金属磁性薄膜材料组成地FeCo/PMN-PT多铁异质结以及磁性纳米薄膜的静态、动态磁化特性和磁电耦合特性和FeCo/Ta多层膜多铁异质结中电场调控剩余磁化强度在信息储存领域的应用。利用射频磁控溅射技术,通过改变制备工艺在PMN-PT(011)衬底上制备了不同磁性薄膜层厚度的FeCo/PMN-PT多铁异质结,研究了在不同工艺下对样品磁性能的影响,同时在矢量网络分析仪(E5071C)上利用传输线微扰法测试出整个测量夹具端口的S参数的差异从而计算推导出样品的微波磁电参数,通过研究磁性薄膜样品矫顽场、磁各向异性和自然共振频率变化,发现初始自然共振频率和磁性薄膜矫顽场的关系以及电场对磁性材料磁各向异性2320e-420Oe的调控,导致样品自然共振频率最大2.96GHz-4GHz的漂移。同时发现电驱动的多铁异质结样品的磁化翻转与薄膜样品中的磁畴的取向和结构变化有关。利用射频磁控溅射设备在PMN-PT(011)衬底上制备了 FeCo/PMN-PT和[FeCo(9m)/Ta(4nm)]5/PMN-PT多铁异质结,分别测量了多铁异质结中剩磁Mr在不同电场条件下的变化。我们发现在FeCo/PMN-PT和[FeCo(9m)/Ta(4nm)]5/PMN-PT多铁异质结中都发现了剩余磁化强度Mr的四态变化,只是在FeCo/PMN-PT异质结中Mr的四态表现的并不稳定而且区分度也不是很高;因此,我们又测量了[FeCo(9m)/Ta(4nm)]5/PMN-PT多铁异质结中的剩余磁化强度,发现了稳定的便于区分的Mr的四态变化。同时,我们还测量了样品的Mr-E和S-E曲线,从物理机制上解释了应变调控的磁电耦合效应导致的多态存储。这就为高密度、大容量的信息储存提供了重要的理论与技术支持。利用磁控溅射技术在(011)方向切割的PMN-PT衬底上沉积了FeCo/FeMn/Ta/PMN-PT、FeGa/FeMn/Ta/PMN-PT 多层膜结构,研究了这种结构的磁电性能、层间耦合等,发现FeMn反铁磁层的引入对两种异质结构的影响存在差异,这是因为在界面处,反铁磁层中的未补偿磁矩相对于FeGa层足够大,而对于FeCo层并不足够大。所以在FeGa/FeMn体系中观察到了矫顽力的变化和交换偏置现象,而在FeCo/FeMn体系中只观察到了明显的矫顽力的变化。
[Abstract]:With the emergence of the third scientific and technological revolution and the rapid development of modern science and technology, the application of multi-iron materials in high performance magnetic devices shows the characteristics of small size, fast speed, high precision and so on. So it is widely used in modern communication technology, information storage system, electromagnetic interference technology and other fields. Multi-iron materials have two or more iron properties, such as ferroelectricity, ferromagnetism and ferroelasticity. And it is important to understand and be able to manipulate the magnetism of ferromagnetic materials in magnetoelectric effect. Multi-iron material systems are usually used to manufacture sensors, multi-state memories and other spin electronic devices. For magnetic thin film materials used in microwave frequency. The characterization of electromagnetic parameters and complex permeability of magnetic materials is also of great significance. In this paper, the composition of monolayer metal magnetic thin films (FeCo/PMN-P) has been studied. T polyferric heterojunction and the static state of magnetic nanocrystalline films. The application of dynamic magnetization and magnetoelectric coupling characteristics and the application of the residual magnetization in the field of information storage in FeCo/Ta multilayer multilayer iron heterojunction. The RF magnetron sputtering technique is used. FeCo/PMN-PT polyferric heterostructures with different thickness of magnetic thin films were prepared on PMN-PTO 011 substrates by changing the preparation process. The effects of different processes on the magnetic properties of the samples were studied. At the same time, by using the transmission line perturbation method, the difference of S parameters of the whole measuring fixture port is measured on the vector network analyzer E5071C, and the microwave magnetoelectric parameters of the sample are calculated. The changes of coercive field, magnetic anisotropy and natural resonance frequency of magnetic thin films were studied. It is found that the relationship between the initial natural resonance frequency and the coercive field of the magnetic thin film and the regulation of the electric field on the magnetic anisotropy 2320e-420Oe. The maximum natural resonance frequency of the sample is 2.96 GHz to 4GHz. It is also found that the magnetization flip of the electrodriven polyferric heterojunction sample is related to the orientation and structure change of the magnetic domain in the thin film sample. RF magnetron sputtering equipment in PMN-PT(). FeCo/PMN-PT and. [5 / 5 PMN-PT polyiron heterojunction. The remanent magnetic Mr (Mr) changes in polyferric heterojunction under different electric fields have been measured respectively. We have found that in the case of FeCo/PMN-PT and. [In the 5 / 5 / PMN-PT multiferroheterojunction, the four-state change of the residual magnetization (Mr) has been found. Only in the FeCo/PMN-PT heterojunction, the four states of Mr are not stable and the degree of differentiation is not very high. So we measured it again. [The residual magnetization in 5 / 5 PMN-PT polyferric heterojunction shows a stable and easily distinguishable Mr four-state change. At the same time. We also measured the Mr-E and S-E curves of the samples and explained from the physical mechanism the polymorphic storage caused by the magnetoelectric coupling effect controlled by strain. This is called high density. Large capacity information storage provides important theoretical and technical support. The FeCo/FeMn/Ta/PMN-PT is deposited on the directionally cut PMN-PT substrate. The magnetoelectric properties and interlaminar coupling of FeGa/FeMn/Ta/PMN-PT multilayer structure are studied. It is found that the influence of the introduction of FeMn antiferromagnetic layer on the two heterostructures is different because the uncompensated magnetic moment in the antiferromagnetic layer is larger than that in the FeGa layer at the interface. However, the FeCo layer is not large enough, so the change of coercivity and exchange bias are observed in FeGa/FeMn system. The change of coercivity was observed only in FeCo/FeMn system.
【学位授予单位】：山东大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O484;TP333

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