The Strain Manipulation of Nanoscale Magnetic Structures

纳米级磁结构的应变操纵

• 批准号: EP/H003487/1
• 负责人: Andrew Rushforth
• 金额: $ 124.86万
• 依托单位: University of Nottingham
• 依托单位国家: 英国
• 项目类别: Fellowship
• 财政年份: 2009
• 资助国家: 英国
• 起止时间: 2009 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FH003487%2F1
• 关键词: Strain; Manipulation; Nanoscale; Magnetic; Structures

Many of the components in modern technological devices such as computers, communications devices (e.g. mobile phones) and sensors are made on a very small scale from magnetic materials. For example, modern computer hard drives and magnetic random access memory (MRAM) contain magnetic elements that are a few tens of nanometres in size. In such devices the direction of the magnetisation of the magnetic elements is used to store information. Controlling the direction of magnetisation is achieved by using electrical current to generate a magnetic field locally or by passing an electrical current through the device using an effect called spin transfer torque . These techniques have disadvantages arising from the energy dissipated in applying electrical currents, the limits on miniaturisation (due to the need to integrate the components which generate the field with other magnetic devices) and the difficulty in addressing individual elements due to stray magnetic fields. A solution to these problems would be to create devices in which the magnetic state is controlled by applying electrical voltages. In this project I will do this by adopting a novel approach, combining the magnetic material with piezoelectric material in hybrid devices. Piezoelectric material has the property that it will physically expand or contract when an electrical voltage is applied to it. This can be used to transfer strain to the magnetic material. Certain magnetic materials have large magnetostrictive properties, which means that if they are strained then the magnetisation direction will rotate. For example, I will study the magnetostrictive transition metal alloys FeCo, FePd and FePt. I will study the magnetic properties of these materials in the bulk and on the nanoscale using modern characterisation techniques such as Superconducting Quantum Interference Device (SQUID) magnetometry and Magnetic Force Microscopy (MFM), and I will use state of the art growth and fabrication techniques (e.g. sputter deposition and electron beam lithography) to fabricate devices a few tens of nanometres in size. By conducting electrical transport experiments at GHz frequencies (comparable to the frequencies used in modern computing technology) I aim to demonstrate ultra-fast switching of the magnetic state of the devices by applying ultra-fast (picosecond) voltage pulses. The nanoscale devices will also be used to study the fundamental physics of phenomena such spin transfer torque . Another class of devices that I will study are nano-electro-mechanical systems (NEMS) which consist of nanoscale oscillating beams and cantilevers. Such devices have potential applications as highly sensitive weighing scales and are also interesting for more fundamental studies of the overlap between quantum and classical physics. The use of magnetostrictive ferromagnetic materials to fabricate NEMS will offer new means to detect and drive the mechanical oscillations.This proposal presents exciting opportunities to study fundamental physical phenomena in new material systems and promises to produce knowledge of new phenomena and new functionalities in nanoscale devices. The results of this work will contribute to the design of future computing, communications and sensor technologies.

现代技术设备（诸如计算机、通信设备（例如，移动的电话）和传感器）中的许多部件都是由磁性材料以非常小的规模制成的。例如，现代计算机硬盘驱动器和磁性随机存取存储器（MRAM）包含大小为几十纳米的磁性元件。在这种装置中，磁性元件的磁化方向用于存储信息。控制磁化方向是通过使用电流来局部产生磁场或通过使用称为自旋转移扭矩的效应使电流通过设备来实现的。这些技术具有由施加电流时耗散的能量、对磁致伸缩的限制（由于需要将产生磁场的部件与其他磁装置集成）以及由于杂散磁场而难以寻址各个元件引起的缺点。这些问题的解决方案将是创建通过施加电压来控制磁状态的设备。在这个项目中，我将采用一种新的方法，将磁性材料与压电材料结合在混合器件中。压电材料具有这样的特性，当电压施加到它上时，它会物理地膨胀或收缩。这可以用来将应变传递到磁性材料。某些磁性材料具有大的磁致伸缩特性，这意味着如果它们受到应变，则磁化方向将旋转。例如，我将研究磁致伸缩过渡金属合金FeCo，FePd和FePt。我将使用现代表征技术，如超导量子干涉器件（SQUID）磁力测量和磁力显微镜（MFM），研究这些材料在批量和纳米尺度上的磁性，我将使用最先进的生长和制造技术（例如溅射沉积和电子束光刻）来制造几十纳米大小的设备。通过在GHz频率（与现代计算技术中使用的频率相当）下进行电传输实验，我的目标是通过施加超快（皮秒）电压脉冲来演示设备磁状态的超快切换。纳米级器件也将用于研究自旋转移力矩等现象的基础物理。我将研究的另一类设备是纳米机电系统（NEMS），它由纳米级振荡梁和杠杆组成。这种设备具有潜在的应用，作为高灵敏度的称重秤，也是有趣的量子和经典物理学之间的重叠更基础的研究。利用磁致伸缩铁磁材料制备NEMS将为检测和驱动机械振荡提供新的手段，为研究新材料体系中的基本物理现象提供了令人兴奋的机会，并有望产生纳米器件中新现象和新功能的知识。这项工作的结果将有助于设计未来的计算，通信和传感器技术。

项目成果

Fast switching of magnetization in the ferromagnetic semiconductor (Ga,Mn)(As,P) using nonequilibrium phonon pulses

使用非平衡声子脉冲快速切换铁磁半导体 (Ga,Mn)(As,P) 中的磁化强度

• DOI: 10.1063/1.3672029
• 发表时间: 2011
• 期刊: Applied Physics Letters
• 影响因子: 4
• 作者: Casiraghi A

Optically excited spin pumping mediating collective magnetization dynamics in a spin valve structure

• DOI: 10.1103/physrevb.98.060406
• 发表时间: 2018-08-13
• 期刊: PHYSICAL REVIEW B
• 影响因子: 3.7
• 作者: Danilov, A. P.;Scherbakov, A. V.;Bayer, M.
• 通讯作者: Bayer, M.

Electrical control of magnetic reversal processes in magnetostrictive structures

• DOI: 10.1063/1.4789396
• 发表时间: 2013-01-21
• 期刊: APPLIED PHYSICS LETTERS
• 影响因子: 4
• 作者: Cavill, S. A.;Parkes, D. E.;Rushforth, A. W.
• 通讯作者: Rushforth, A. W.

Deterministic control of magnetic vortex wall chirality by electric field.

• DOI: 10.1038/s41598-017-07944-9
• 发表时间: 2017-08-08
• 期刊: Scientific reports
• 影响因子: 4.6
• 作者: Beardsley RP;Bowe S;Parkes DE;Reardon C;Edmonds KW;Gallagher BL;Cavill SA;Rushforth AW
• 通讯作者: Rushforth AW

Optically driven spin pumping mediating collective magnetization dynamics in a spin valve structure

光学驱动的自旋泵浦介导自旋阀结构中的集体磁化动力学

• DOI: 10.48550/arxiv.1805.07669
• 发表时间: 2018
• 作者: Danilov A