Radical-Bridged Lanthanide Molecular Nanomagnets

稀土金属如钕、铽和镝具有不同寻常的和非常理想的磁性;它们的一些合金是已知最强的永磁体。稀土磁体在包括计算机硬盘驱动器在内的一系列环境中有着广泛的应用。磁性材料对于计算特别重要，因为它们提供了将数字信息传输到信息存储单元、存储在信息存储单元内以及从信息存储单元读取的手段。存储单元通常由磁畴的集合组成，其中有序发生在数百纳米的维度上。磁畴的大小至关重要，因为它决定了可以存储和处理的信息量。当今社会面临的最重要的任务之一是找到处理所谓大数据的方法。大数据是指大量出现且性质日益复杂的数字信息。使用传统的磁存储介质处理大数据最终将被证明是不可能的，因此开发新的信息存储设备是一个巨大的挑战。成功应对这一挑战的关键是微型化，因此该项目将开发新一代分子尺度的磁性材料，其尺寸仅为几纳米。该项目所关注的分子材料被称为单分子磁体（SMM）。与传统的永磁体相比，SMM是离散的分子纳米磁体，其保持磁化的方式不依赖于跨越大距离的相互作用，因此它们提供了独特的特性，已被提议作为超高密度信息技术的基础，以前所未有的快速度进行处理。SMM也被提议作为纳米尺度分子自旋电子器件的工作组件。SMM的缺点是，所有示例都只能在液氦温度下工作：该项目将开发在更实际温度下工作的SMM，这将引入开发原型设备的可能性。更广泛地说，实现该项目的目标将为推进EPSRC功能材料纳米级设计大挑战做出重要贡献。该项目的目标将通过基于分子稀土化合物的创新合成策略来实现，其中金属中心由一系列新型磁性有机基团连接。该项目将实现的关键进展将是磁性有机连接器，它提供了一种创新的方法来防止关闭SMM磁性记忆的过程。分子设计过程的一个重要特征是能够在原子水平上改变磁性，例如，将连接稀土金属的原子从磷转换为砷，以及从砷转换为其他主族元素。或者，也已经提出了一系列具有通过靶向化学修饰改变其磁矩的能力的有机连接体，这是一种允许微调SMM性质的策略。实验方法将通过高级理论计算进行补充，这将为新的SMM提供详细的见解，并将为开发改进的系统提供合理的方法。最终，我们将开发在液氮冷却可以达到的温度下运行的SMM。这些材料将代表分子纳米磁性的一个台阶式变化，并将对整个科学界产生巨大影响，并有可能在社会中产生更广泛的影响。

Rare-earth metals such as neodymium, terbium and dysprosium have unusual and highly desirable magnetic properties; some of their alloys are amongst the strongest known permanent magnets. Rare earth magnets have widespread applications in a range of settings, including computer hard-disk drives. Magnetic materials are particularly important for computing because they provide the means by which digital information is transferred to, stored within, and read from an information storage unit. The storage unit typically consists of a collection of magnetic domains, where ordering occurs across dimensions of hundreds of nanometres. The size of the magnetic domain is crucial because it determines the amount of information that can be stored and processed.One of the most important tasks facing society today is to find ways of dealing with so-called Big Data, the term used to describe digital information that occurs in vast amounts and is of an increasingly complex nature. Processing Big Data with conventional magnetic storage media will eventually prove to be impossible, hence the development of new information storage devices is the grand challenge. The key to success with this challenge is miniaturization, hence this project will develop a new generation of magnetic materials on the molecular scale, with dimensions of only a few nanometres.The molecular materials with which this project is concerned are known as single-molecule magnets (SMMs). In contrast to traditional permanent magnets, SMMs are discrete molecular nano-magnets that retain magnetization in ways that do not rely on interactions across large distances, hence they offer unique properties that have been proposed as the basis of ultrahigh-density information technology, with processing at unprecedentedly fast speeds. SMMs have also been proposed as the working components of nano-scale molecular spintronic devices. The drawback with SMMs is that all examples function only at liquid-helium temperatures: this project will develop SMMs that function at more practical temperatures, which will introduce the possibility of developing prototype devices. More broadly, achieving the aims of this project will make an important contribution towards advancing the EPSRC Nanoscale Design of Functional Materials Grand Challenge.The aims of the project will be achieved using innovative synthetic strategies based on molecular rare earth compounds in which the metal centres are linked by a series of novel magnetic organic groups. The key advance that will be enabled by this project will be with the magnetic organic linkers, which provide an innovative way of preventing the processes that otherwise switch off the magnetic memory of SMMs. An important feature of the molecular design process is the ability to change the magnetic properties at the atomic level by, for example, switching the atoms that connect the rare earth metals from phosphorus to arsenic, and from arsenic to other main group elements. Alternatively, a family of organic linkers with the capacity to change their magnetic moments via targeted chemical modifications have also been proposed, a strategy that will allow fine tuning of SMM properties. The experimental approach will be complemented by high-level theoretical calculations, which will provide detailed insight into the new SMMs and will provide a rational way of developing improved systems.Ultimately, we will develop SMMs that function at temperatures that can be reached by cooling with liquid nitrogen. Such materials would represent a step-change in molecular nanomagnetism, and would result in tremendous impact across the scientific community, with the potential to make impact more widely in society.