兰州大学机构库 >物理科学与技术学院
磁畴壁和涡旋态自旋动力学的微磁学研究
Alternative TitleMicromagnetic Studies of Domain Walls and Vortices
朱起源
Subtype博士
Thesis Advisor朱起源
2015-05-27
Degree Grantor兰州大学
Place of Conferral兰州
Degree Name博士
Keyword畴壁 涡旋态 自旋转移矩 微磁学模拟
Abstract自旋转移矩(Spin-transfer Torque, STT)效应的发现,使得在磁性纳米结构中操纵局域磁矩的动力学过程成为可能。在不借助于外加磁场的情况下,STT有足够的能力激发磁矩进动,实现不同类型的磁化动力学过程,比如磁化反转,磁畴壁移动和磁矩的稳定进动等。带状或柱状磁性纳米结构中磁特性的研究不仅可以为磁化动力学过程提供一个更为深入的理解,而且对于实现广泛的技术应用具有重大的意义。近年来随着对纳米结构中磁特性的深入研究,赛道存储器,微波振荡器以及磁场传感器等一系列新颖的概念被提出甚至已经实现相关的技术用。 本论文采用微磁学方法,主要研究了不同的纳米体系中自旋转移矩对磁畴壁和涡旋态的动力学过程的作用。对磁畴壁的研究,我们主要关注在畴壁移动过程中一个非常重要的现象—Walker breakdown,并通过各种方法提高Walker 极限进而提高畴壁的移动速度。在另一部分关于磁涡旋态的工作中,对涡旋核的进动以及相互耦合的两涡旋核之间相位锁定过程进行了深入的研究。这部分工作可以为基于涡旋态的自旋纳米振荡器的设计以及应用提供必要的理论基础及设计思路。
Other AbstractThe spin-transfer torque (STT) induced by spin-polarized current was found to be an efficient method to manipulate the magnetization in magnetic nanostructures. Without the aid of external magnetic field, different types of dynamical states induced by STT can occur, such as magnetization reversal, domain wall motion, and persistent precession, etc. The research on magnetic properties in nanostructures not only makes it possible to understand the magnetic dynamics, but also important for potential applications. A series of applications, such as racetrack memory, microwave oscillator, and magnetic sensor, have been achieved with the deeper studying on the properties in magnetic nanostructures. In this work, dynamics of domain walls and vortices in different nanostructures have been studied by micromagnetic simulation. For the research on domain wall, we focus on an important phenomenon in domain wall motion, known as Walker Breakdown. We discuss possible solutions to suppress Walker breakdown and enhance the domain wall velocity. In another part of the work, we performed a systematic study on the dynamics of vortices, as well as the phase locking between two vortices. The systematic study of phase locking process is important for the designs and applications of vortex-based STNOs.
URL查看原文
Language中文
Document Type学位论文
Identifierhttps://ir.lzu.edu.cn/handle/262010/230264
Collection物理科学与技术学院
Recommended Citation
GB/T 7714
朱起源. 磁畴壁和涡旋态自旋动力学的微磁学研究[D]. 兰州. 兰州大学,2015.
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