Size, shape and surface properties in realistic models of magnetic nanocrystals

磁性纳米晶体真实模型中的尺寸、形状和表面特性

• 批准号: EP/P022006/1
• 负责人: Richard Evans
• 金额: $ 12.82万
• 依托单位: University of York
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2017
• 资助国家: 英国
• 起止时间: 2017 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FP022006%2F1
• 关键词: Size; shape; surface; properties; realistic

Magnetic hyperthermia is a promising treatment for brain and prostate cancers due to the localised nature of the treatment compared to chemo or radiotherapy. Brain cancer in particular is difficult to treat with conventional therapies due to the sensitivity of the surrounding tissue with only a 14% survival rate after 10 years in the UK. Magnetic nanoparticles used in magnetic hyperthermia must be biocompatible and provide efficient and reliable heating, yet their physical complexity is limiting progress towards their clinical use. Complexity arises due to the small size of the particles (10-100 nm) leading to a range of physical properties such as surface and bulk atomic defects, finite size and thermal effects, multiple oxide phases and surface functionalization. All of these properties contribute to the overall magnetic properties but are extremely difficult to predict theoretically or with simple model approaches. Previous simulations have considered only simple approaches to the magnetic properties of individual magnetic nanoparticles and give limited insight into the properties of real nanoparticles. Yet there is an urgent need to understand the relative importance of these effects so that experimental effort can be focused on their control and optimisation to accelerate development of this potentially life saving treatment. This proposal will address this challenge by developing a realistic model of magnetic nanoparticles to understand the role of the surface on the particle properties and the resulting magnetization dynamics used to generate heat during magnetic hyperthermia. The aim of the project is to develop a novel atomic scale magnetic model of magnetite nanocrystals to understand the effects of size, shape and the surface on their equilibrium and dynamic magnetic properties. We will use this information to model and understand how the magnetic particles reverse in an applied magnetic field which is directly related to the amount of heat generated during magnetic hyperthermia. Using atomistic spin dynamics we will be able to simulate the effects of thermal fluctuations at the surface on the effective magnetic properties and their importance in determining the reversal mechanism. The interactions between particles can also play a critical role in the overall magnetic properties, and so we will use our model to simulate the interaction of small clusters of particles with atomic resolution giving new insight into their importance. Finally, we will develop an atomistic model of functional core-shell oxide nanoparticles to determine the optimal magnetic properties for magnetic hyperthermia. The computational methods developed in this project will significantly advance the ability to accurately model magnetic composite materials with wide application in the fields of magnetism and spintronics and made freely available to the community within the open source vampire software package. The results from this project will improve our understanding of the properties of magnetite nanocrystals, guide future research on magnetic hyperthermia and accelerate the development of this critical treatment.

由于治疗的局部性质，与化学疗法或放射疗法相比，磁性高温是对脑和前列腺癌的有前途的治疗方法。特别是由于周围组织的敏感性，在英国10年后仅14％的存活率，脑癌尤其难以治疗常规疗法。磁性热疗中使用的磁性纳米颗粒必须具有生物相容性并提供有效且可靠的加热，但是它们的身体复杂性却限制了其临床使用的进展。由于颗粒的尺寸较小（10-100 nm），因此出现了复杂性，导致了一系列物理特性，例如表面和散装原子缺陷，有限的大小和热效应，多个氧化物相以及表面功能化。所有这些特性都有助于整体磁性，但在理论上或使用简单的模型方法进行预测非常困难。先前的模拟仅考虑了单个磁性纳米颗粒的磁性特性的简单方法，并对真实纳米颗粒的性质有限的见解有限。然而，迫切需要了解这些影响的相对重要性，以便可以将实验努力集中在其控制和优化上，以加快这种潜在的挽救生命的治疗。该建议将通过开发磁性纳米颗粒的现实模型来理解表面在粒子特性上的作用以及用于在磁性高热期间产生热量的磁化动力学的作用来解决这一挑战。该项目的目的是开发一种新型的磁铁矿纳米晶体磁模型，以了解大小，形状和表面对其平衡和动态磁性特性的影响。我们将使用此信息来建模并了解与磁性高热期间产生的热量直接相关的施加磁场中的磁颗粒如何反向。使用原子自旋动力学，我们将能够模拟表面热波动对有效磁性特性的影响及其在确定逆转机制方面的重要性。粒子之间的相互作用也可以在整体磁性特性中起关键作用，因此我们将使用模型模拟与原子分辨率的小颗粒簇的相互作用，从而有了新的见解。最后，我们将开发一种功能性核心氧化物纳米颗粒的原子模型，以确定磁性高温的最佳磁性。该项目中开发的计算方法将显着提高能够在磁性和旋转型领域中准确地对具有广泛应用的磁性复合材料进行建模，并在开源吸血鬼软件包中自由地向社区免费提供。该项目的结果将提高我们对磁铁矿纳米晶体特性的理解，指导未来的磁性高温研究，并加速这种关键处理的发展。

项目成果

The role of faceting and elongation on the magnetic anisotropy of magnetite Fe3O4 nanocrystals

• DOI: 10.1038/s41598-020-58976-7
• 发表时间: 2019-09
• 期刊: Scientific Reports
• 影响因子: 4.6
• 作者: R. Moreno;S. Poyser;Daniel Meilak;A. Meo;Sarah Jenkins;V. Lazarov;G. Vallejo-Fernandez;S. Majetich;R. Evans

Properties and dynamics of meron topological spin textures in the two-dimensional magnet CrCl3

二维磁体 CrCl3 中 Meron 拓扑自旋织构的性质和动力学

• DOI: 10.48550/arxiv.2012.03296
• 发表时间: 2020
• 作者: Augustin M

Role of anti-phase boundaries in the formation of magnetic domains in magnetite thin films

反相边界在磁铁矿薄膜磁畴形成中的作用

• DOI: 10.48550/arxiv.2001.01766
• 发表时间: 2020
• 作者: Moreno R

Enhancement of intrinsic magnetic damping in defect-free epitaxial Fe3O4 thin films

• DOI: 10.1063/1.5091503
• 发表时间: 2017-10
• 期刊: Applied Physics Letters
• 影响因子: 4
• 作者: Xianyang Lu;L. Atkinson;B. Kuerbanjiang;Bo Liu;Guanqiao Li;Yichuan Wang;Junlin Wang;X. Ruan