Advanced Characterisation of Magnetic Recording Media using Neutron Scattering

使用中子散射对磁记录介质进行高级表征

• 批准号: EP/E038514/1
• 负责人: Stephen Lee
• 金额: $ 47.57万
• 依托单位: University of St Andrews
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2007
• 资助国家: 英国
• 起止时间: 2007 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FE038514%2F1
• 关键词: Advanced; Characterisation; Magnetic; Recording; Media

Magnetic hard disk storage devices are found at the heart of many of the high technology system we take for granted in modern life. As essential components of devices such as computers, modern video storage devices and mp3 players, they permeate much of our business and leisure activities and are thus of enormous commercial importance. These devices offer significant advantages over other current technologies. When this pre-eminence is coupled with the insatiable demand for higher recording density and smaller devices, the commercial importance of this technology is assured for some years to come.At the heart of every hard disk drive are highly advanced materials, 'recording media', that are a tour de force of materials' science and technology. These materials are deposited as thin films (ca. 20 nm thick) onto the surface of a disk that is typically around 6-9 cm in diameter. Information may be stored since the recording media are ferromagnetic, and the magnetic alignment of small areas of the disk ('bits') is controlled by a tiny micro-machined electromagnet that scans across the surface of the disk as it rotates at a rate of around 10000 revolutions per minute or greater. The materials are formed from small grains that are remarkably similar in size, typically 8 nm with a a variation of around 22-30%, depending on the materials. Each ferromagnetic bit is formed from around 200 of these grains. Due to their obvious market pre-eminence there is a very large body of literature concerned with the characterization and performance characteristics of these materials. Rather surprisingly, there has been relatively very little investigation of their magnetic properties on the length scale of the grains themselves. This is to some large extent due to the problems of finding appropriate physical probes that can produce quantitative results at these (sub-10 nm) length scales. Over recent years we have worked in collaboration with several of the world market leaders in magnetic storage technology (Seagate, IBM, Hitachi) to address fundamental questions about the physical and magnetic structure of magnetic recording media. This work is not routine characterisation, but seeks to reveal relevant and generic properties that could have important implications for future media design, particularly by providing insight that enhances the correct modelling of these materials. Micromagnetic modelling is a vital component of the modern media industry, since it allows the optimisation of performance in increasingly complex and elaborate device and materials configurations. Neutrons provide an ideal way to measure the magnetic structure at the granular level since they:i) Have a magnetic moment that allows them to scatter off magnetic variations in the sampleii) Have a wavelength that allows scattering from variations on the length scale of interest (in this case 1- 30 nm)ii) Have a weak interaction with matter so do not (in this instance) disturb the system which they are measuring.Our recent work with market leaders makes use of world leading neutron facilities to reveal unique and important information on the sub-10 nm magnetic structure, that could greatly assist the future design and modelling of these materials. We have a position in this field that is currently world leading. However, we require more serious resourcing of this programme to allow us both to expand the project but moreover to allow us to do the experiments that will ensure the impact for this work for which it has the potential. It is timely, since we currently have in place access to the latest materials (Hitachi) and guaranteed access to significant dedicated beamtime (PSI), as well as further opportunites via responsive mode beam time application to ISIS and the ILL, for which we have an excellent record. It thus provides an opportunity for a UK based group using UK and European facilities to play a role in a field usually dominated by US researc

磁性硬盘存储设备是现代生活中许多高科技系统的核心，我们认为这是理所当然的。作为计算机、现代视频存储设备和mp3播放器等设备的重要组成部分，它们渗透到我们的许多商业和休闲活动中，因此具有巨大的商业重要性。与其他现有技术相比，这些设备具有显著的优势。当这种卓越与对更高记录密度和更小设备的永不满足的需求相结合时，这项技术在未来几年的商业重要性是肯定的。每个硬盘驱动器的核心都是高度先进的材料，“记录介质”，这是材料科学和技术的杰作。这些材料以薄膜（约20纳米厚）的形式沉积在直径通常约为6-9厘米的圆盘表面。由于记录介质是铁磁性的，信息可以被存储，磁盘小区域（“位”）的磁排列是由一个微小的微机械电磁铁控制的，当磁盘以每分钟大约10000转或更高的速度旋转时，电磁铁扫描磁盘表面。这些材料是由小颗粒组成的，它们的尺寸非常相似，通常为8纳米，根据材料的不同，变化幅度在22-30%左右。每个铁磁钻头由大约200个这样的颗粒组成。由于其明显的市场优势，有一个非常大的文献体关注这些材料的特性和性能特点。令人惊讶的是，在晶粒本身的长度尺度上，对其磁性的研究相对很少。这在很大程度上是由于寻找合适的物理探针的问题，这些探针可以在这些（低于10纳米）长度尺度上产生定量结果。近年来，我们与磁性存储技术的几个世界市场领导者（希捷，IBM，日立）合作，解决有关磁性记录介质的物理和磁性结构的基本问题。这项工作不是常规的特征描述，而是试图揭示相关和通用的属性，这些属性可能对未来的媒体设计产生重要影响，特别是通过提供增强这些材料正确建模的见解。微磁建模是现代媒体行业的重要组成部分，因为它可以在日益复杂和精心设计的设备和材料配置中优化性能。中子提供了一种在颗粒水平上测量磁性结构的理想方法，因为它们：i)具有磁矩，使它们能够散射样品中的磁性变化；ii)具有波长，允许从感兴趣的长度尺度的变化中散射（在这种情况下为1- 30 nm）ii)与物质有弱相互作用，因此不会（在这种情况下）干扰它们正在测量的系统。我们最近与市场领导者合作，利用世界领先的中子设施，揭示了10纳米以下磁性结构的独特和重要信息，这可以极大地帮助这些材料的未来设计和建模。我们在这一领域处于世界领先地位。然而，我们需要对这一方案进行更严格的资源配置，使我们不仅能够扩大项目，而且能够进行实验，以确保对这项工作产生潜在的影响。这是及时的，因为我们目前可以获得最新的材料（日立），并保证获得显著的专用波束时间（PSI），以及通过响应模式波束时间应用于ISIS和ILL的进一步机会，我们在这方面有很好的记录。因此，它为英国集团提供了一个机会，利用英国和欧洲的设施，在一个通常由美国研究主导的领域发挥作用

项目成果

Analysing SANS data to determine magnetisation reversal processes in composite perpendicular magnetic recording media using TEM images Dedicated to Prof. Dr.-Ing. Heinrich Wollenberger on the occasion of his 80 th birthday

使用 TEM 图像分析 SANS 数据以确定复合垂直磁记录介质中的磁化反转过程 献给工程博士教授。

• DOI: 10.3139/146.110562
• 发表时间: 2011
• 期刊: International Journal of Materials Research
• 影响因子: 0.8
• 作者: Lister S