New Physics in Artificial Spin Ice via Materials Innovation

磁性材料在技术上是极其重要的，纳米级尺寸的磁铁在诸如硬盘驱动器等一系列应用中尤为重要。这种微小的“纳米磁铁”的基本物理学也令人兴奋，因为它们的集合表现出在任何其他物理系统中无法观察到的行为，并且可以非常精确地控制。这些纳米磁铁的集合被精心设计成阵列，被称为“人工自旋冰”，因为它们与冰中的水分子有一些共同的潜在物理特性。这个研究项目研究的是由精心挑选的材料组成的人工自旋冰，这些材料会产生各种不同寻常的行为，否则这些行为是无法达到的，一旦被探索和理解，它们可能具有重大的技术意义。虽然这一领域的绝大多数先前的研究只使用简单的磁性材料，但这项工作将引入更多的奇异材料来获取特定的、不寻常的和潜在有用的物理。除了与可能的技术联系之外，这项研究还将对本科生和研究生的教育做出重大贡献，研究成果将为研究人员的工作提供信息，代表全国更大的研究生态系统。技术摘要：该研究项目将通过两名在材料制造、表征和磁性测量方面具有高度互补专业知识的研究人员之间的合作，通过战略性选择、创新铁磁材料制造阵列，显著扩展可在人工自旋冰中探测的物理学。研究将集中在三个方面：1。新的人工自旋冰物理由指向结构平面外的磁矩实现，探索平面内力矩无法实现的合作现象。2. 强温度依赖磁化条件下的人工自旋冰行为和超顺磁性。3. 通过连接人工自旋冰网络的紧急材料诱导的电子输运现象。研究结果可能在新的计算范式和磁振学中具有技术相关性。本科生和研究生研究人员将深入参与研究工作，并将获得一系列技能，以促进他们的专业发展。两位研究者还将利用他们参与的各种活动来进一步支持国家研究界。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Non-Technical AbstractMagnetic materials are extremely important technologically, and magnets that have size scale in the range of nanometers are especially important in a range of applications, such as hard disk drives. The fundamental physics of such tiny “nanomagnets” is also exciting, because collections of them show behavior that cannot be observed in any other physical system and can be controlled very precisely. Collections of these nanomagnets in certain carefully designed arrays are called “artificial spin ice” because they share some underlying physics with water molecules in ice. This research program studies such artificial spin ice composed of carefully chosen materials that result in a wide range of unusual behavior that would otherwise be inaccessible and could have significant technological implications once explored and understood. While the vast majority of prior research in this area uses only simple magnetic materials, this work will introduce more exotic materials to access specific, unusual, and potentially useful physics. Aside from connections to possible technologies, the research will also contribute substantially to the education of both undergraduate and graduate students, and the research efforts will inform the investigators’ work on behalf of the larger research ecosystem in the nation.Technical Abstract The research program will significantly expand the physics that can be probed in artificial spin ice by fabricating arrays from strategically chosen, innovative ferromagnetic materials through a collaboration between two investigators with highly complementary expertise, in materials fabrication and characterization, and magnetic measurements. The research will focus on three thrusts: 1. New artificial spin ice physics enabled by magnetic moments that point out of the plane of the structures, exploring cooperative phenomena that are inaccessible with in-plane moments. 2. Artificial spin ice behavior and superparamagnetism in the regime of strongly-temperature-dependent magnetization. 3. Emergent materials-induced electronic transport phenomena through networks of connected artificial spin ice. The research findings may have technological relevance in new computing paradigms and in magnonics. Undergraduate and graduate student researchers will be deeply involved in the research efforts and will gain a range of skills to advance their professional development. Both investigators will also leverage their involvement in various activities to further support the national research community.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.