Designer 3D Magnetic Mesostructures

设计师 3D 磁性细观结构

• 批准号: EP/E039944/1
• 负责人: Simon Bending
• 金额: $ 59.45万
• 依托单位: University of Bath
• 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%2FE039944%2F1
• 关键词: Designer; 3D; Magnetic; Mesostructures

In a remarkable recent paper Xiao et al. at Argonne National Laboratories demonstrated that 'architecture-tuneable' Pb mesostructures (samples whose dimensions lie between microscopic 'atomic' scales and macroscopic 'bulk' scales at which the specific geometry no longer plays a role for physical properties) can be grown by electrodeposition from lead salt solutions onto graphite substrates. Simply varying the electrode potentials allows an extraordinary variety of different sample morphologies to be realised, ranging from regular polyhedra and nanowires to multipods and 'snowflakes'. These structures are truly three-dimensional (3D) superconducting mesocrystals with few bulk defects and perfectly smooth faceted faces, whose magnetic properties are dominated by their size and shape. The same deposition method should be readily extendable to many ferromagnetic metals and alloys. For the first time it is now possible to controllably fabricate regular faceted 3D mesoscrystals without the disorder and rough surfaces/edges characteristic of lithographically-patterned thin film structures. Crucially, the dimensions of these 3D mesostructures are comparable with the relevant characteristic lengthscales found in ferromagnetism and superconductivity (e.g. ferromagnetic domain size and/or domain wall width or superconducting coherence length and/or magnetic field penetration depth) in contrast to widely studied nanoscale particles/clusters and nanowires. Competition between different processes as a function of the size and shape of these 3D structures should lead to rich new physical phenomena with strong potential for exploitation. In collaboration with the Argonne group we have shown that surface/shape effects can completely dominate the magnetisation of these materials, opening up the possibility of 'designing' crystals with desirable, exploitable properties. We propose to considerably extend the scope of this work within a collaboration between well established groups in electrochemistry and nanoscale physics at the University of Bath and theoreticians in Southampton and Antwerp. We plan to grow and investigate both superconducting and ferromagnetic mesocrystals with a wide range of morphologies, as well as hybrid ferromagnetic-superconductor core-shell structures and continuous hybrid networks. The most promising materials produced will be systematically characterised using Hall nanomagnetometry and/or magnetoresistance measurements. Experimental results will be interpreted by comparison with tailor-made state-of-the-art 3D micromagnetic simulations and/or solutions of the 3D Ginzburg-Landau equation. Opportunities for exploitation of these novel magnetic materials will also be identified and explored.

阿贡国家实验室的Xiao等人在最近的一篇引人注目的论文中证明，“结构可调”的Pb介观结构（尺寸介于微观“原子”尺度和宏观“体”尺度之间的样品，在这种尺度下，特定的几何形状不再对物理性质起作用）可以通过从铅盐溶液电沉积到石墨基底上来生长。简单地改变电极电位就可以实现各种不同的样品形态，从规则的多面体和纳米线到多脚和“雪花”。这些结构是真正的三维（3D）超导介晶，具有很少的体缺陷和完美光滑的小面，其磁性由其尺寸和形状决定。同样的沉积方法应该很容易扩展到许多铁磁金属和合金。对于第一次，现在可以可控地制造规则的刻面3D介晶，而没有光刻图案化的薄膜结构的无序和粗糙表面/边缘特性。至关重要的是，这些3D介观结构的尺寸与铁磁性和超导性中发现的相关特征长度尺度（例如铁磁畴尺寸和/或畴壁宽度或超导相干长度和/或磁场穿透深度）相比，与广泛研究的纳米级颗粒/簇和纳米线相比。作为这些3D结构的大小和形状的函数，不同过程之间的竞争应该会导致丰富的新物理现象，具有很强的开发潜力。在与阿贡小组的合作中，我们已经证明了表面/形状效应可以完全主导这些材料的磁化强度，从而开辟了“设计”具有理想的可开发特性的晶体的可能性。我们建议大大扩展这项工作的范围内，在巴斯大学和理论家在南安普顿和安特卫普的电化学和纳米物理学之间的合作。我们计划生长和研究具有各种形态的超导和铁磁介晶，以及混合铁磁超导核壳结构和连续混合网络。最有前途的材料生产将系统地使用霍尔纳米磁学和/或磁阻测量。实验结果将通过与定制的最先进的3D微磁模拟和/或3D Ginzburg-Landau方程的解决方案进行比较来解释。还将确定和探索利用这些新型磁性材料的机会。