Exchange-coupled magnetic metamaterials: fabrication, structure-property correlations, and applications

非技术摘要本项目致力于通过光刻方法制造纳米级磁体阵列的排列和性质。基本物理部分将调查，无论是通过实验和建模，稳定的磁配置的阵列受到不同的扰动所引入的不同的磁性底层。它还将研究（a）将这种阵列用于信息存储的下一代磁记录介质的可能性，以及（B）开发用于信息处理中的逻辑功能的磁方法。我们将研究可以提供急需的额外自由度来设计新的属性，功能和应用程序的相互作用。这一建议还将使PI能够联合收割机将发现与教学，培训，学习以及适当的商业化同步推进。技术摘要单畴纳米级磁性元件通过光刻法制造，并形成有序阵列，形成具有不寻常性能的优异磁性超材料。通常，它们的行为由宏观元件间偶极相互作用主导，但除此之外，我们还提出微观交换相互作用，以提供在三个不同领域设计新性能、功能和应用所急需的额外自由度：（1）纳米级铁磁岛晶格中的几何挫折具有偶极相互作用，导致形成自旋冰配置;在这里，我们打算研究自旋冰超材料的材料物理和磁结构，包括它的热力学相变，通过底层耦合，其中自旋晶格的纳米元素之间的相互作用由横向交换偏置（EB）主导。在自旋冰构型演化的不同阶段，也可以沿沿着不同的明确的结晶学方向将EB加入系统。(2)或者，超材料中的每个元素可以是多层的，具有元素内交换相互作用;这种交换耦合的复合超材料的磁性能，通过纳米压印光刻在大面积阵列中制造，将针对位图案化介质进行优化。(3)在特定纳米磁性阵列中的磁量子细胞自动机（MQCA）处理信息和执行布尔逻辑运算是CMOS技术的一个有前途的替代方案。我们将基于一种新的亚50 nm纳米磁体元件设计，首次设计和构造执行基本布尔逻辑运算的交换耦合逻辑门;两个代表性的门（与和或），将被证明。微磁建模和材料表征，无论是常规的还是先进的，使用电子，光子和扫描探针，将提供对结构-性质性能相关性的基本见解，在适当的长度尺度上，所有这些独特的和定制的超材料。这一提议还将使PI能够将发现的巨大进步与教学，培训，学习以及适当的商业化结合起来。

Non-Technical AbstractThis project addresses the arrangement and properties of arrays of nanoscale magnets fabricatedby lithography methods. The fundamental physics component will investigate, both byexperiment and modeling, the stable magnetic configuration of such arrays subject to differentperturbations introduced by different magnetic underlayers. It will also investigate the possibilityof (a) using such arrays for next generation magnetic recording media for information storage, and(b) developing a magnetic approach for logic function in information processing. We will study interactions that can provide much needed additional freedom toengineer new properties, functionalities and applications. This proposal will also enable the PI to combine the simultaneous advancement of discovery with teaching, training, learning, and if appropriate, commercialization. Technical AbstractSingle domain, nanoscale magnetic elements, fabricated by lithography, and patterned intoordered arrays, form excellent magnetic metamaterials with unusual properties. Typically, theirbehavior is dominated by macroscopic inter-element dipolar interactions, but here in addition, wepropose microscopic exchange interactions to provide much needed additional freedom toengineer new properties, functionalities and applications in three distinct areas:(1) Geometrical frustration in a lattice of nanoscale ferromagnetic islands with dipolar interactions,leads to the formation of a spin-ice configuration; here we propose to investigate the materialsphysics and magnetic configuration of a spin-ice metamaterial, including its thermodynamic phasetransitions, coupled through underlayers where the interactions between the nanoelements of thespin lattice are dominated by lateral exchange bias (EB). The EB, along different well-definedcrystallographic directions, can also be added to the system at different stages of the spin-iceconfigurational evolution.(2) Alternatively, each element in the metamaterial can be a multilayer, with intra-elementexchange interactions; the magnetic performance of such exchange exchange-coupled compositemetamaterial, fabricated in large-area arrays by nanoimprint lithography, will be optimized for bitpatternedmedia.(3) Magnetic quantum cellular automata (MQCA) in specific nanomagnetic arrays to processinformation and perform Boolean logic operations is a promising alternative to CMOS technology.We will design and construct, for the first time, exchange-coupled logic gates that performelementary Boolean logic operations, based on a novel design of sub-50nm nanomagnet elements;two representive gates (AND and OR), will be demonstrated.Micromagnetic modeling and materials characterization, both routine and advanced, usingelectrons, photons and scanning probes, will provide fundamental insight into the structure- property performance correlation, at appropriate length scales, of all these unique and tailoredmetamaterials. This proposal will also enable the PI to combine the simultaneousadvancement of discovery with teaching, training, learning, and if appropriate, commercialization.