U.S.-Ireland R&D Partnership: Molecular Magnetoelectric Materials

非技术概述这一合作项目涉及美国、爱尔兰共和国和北爱尔兰的合作伙伴，重点是实现对一种新型材料的分子级别控制，这种材料具有在环境温度下很容易切换的电和磁性能。该项目得到了材料研究部固体和材料化学计划和凝聚态物理计划的支持。尤其重要的是，可以通过选择特定的分子构建块来调节不同材料属性之间的耦合，从而可以利用通常只切换电属性的外部刺激来切换例如磁状态，反之亦然。这种多功能的行为可能会以非常低的能耗为超高速存储应用铺平道路，从而解决电子设备继续小型化的最重要障碍之一(摩尔定律)。研究活动集中在化学合成、所得材料的精确表征以及制造纳米级器件结构的途径上。因此，预计将在几个层面上产生影响，主要是在变革性的基础科学方面，但也增加了对导致21世纪新技术的分子设计原则的理解。这个高度跨学科和跨国的联盟为早期博士和博士后研究人员提供了极好的培训和流动机会，资助团队中女性参与率达到40%-60%的目标将促进性别平等。美国-爱尔兰三方联盟还确保爱尔兰岛、北部和南部的团队之间进行有意义的跨境合作，从而努力实现建设繁荣和全岛经济的双重目标，并继续两个司法管辖区之间的和平与和解工作。技术概述这个合作项目由材料研究部的固态和材料化学计划和凝聚态物理计划支持，制定了利用某些顺磁过渡金属络合物中出现的可切换电子自旋态的方法来开发新型磁电材料。目标化合物是自旋交叉的金属有机化合物，它可以在加热、光激发、压力/应变或电场和磁场的作用下，改变d轨道上电子的内部排列，从配对变为不配对。该项目研究了在一系列扰动下伴随自旋态转换而来的电、磁和结构性质的变化之间的相互作用。还探索了实现结晶型金属有机物纳米加工的途径。四个跨学科的子项目被研究：(1)合成路线的优化，以确保(I)在极性铁电空间群中的结晶和(Ii)保持热自旋态切换；(2)表征(I)自旋态和(Ii)铁电畴结构；(3)自旋态和电极化的磁、电、光和应变开关的潜力；以及(4)将金属有机物从晶体纳米制备成薄膜上的阵列。对具有软晶格的基于分子的金属有机物的关注提供了一种替代的和有利的途径，以获得具有室温下容易切换的磁极化和电极化响应的材料，以及未来超高速、低能量存储应用的潜力。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Non-Technical SummaryThis collaborative project involving partners in the US, the Republic of Ireland and Northern Ireland, focuses on achieving molecular-level control of a new class of materials that possess both electric and magnetic properties that are readily switchable at ambient temperatures. The project is supported by the Solid State and Materials Chemistry program and the Condensed Matter Physics program, both in the Division of Materials Research. Of particular importance is the possibility to tune the coupling between the different material properties by choosing particular molecular building blocks, so that it becomes possible to switch, for example, the magnetic state with an external stimulus that would ordinarily switch only the electric property, and vice versa. This multi-functional behavior can potentially pave the way towards ultra-fast memory storage applications with very low energy consumption, thereby solving one of the most significant roadblocks to the continued miniaturization of electronic devices (Moore’s law). Research activities focus on chemical synthesis, precise characterization of the resulting materials, and routes towards fabrication of nanoscale device structures. Impacts are therefore expected at several levels, chiefly in terms of transformative fundamental science, but also increased understanding of molecular design principles leading to new technologies for the 21st century. The highly interdisciplinary and transnational consortium provides excellent training and mobility opportunities to early stage PhD and postdoctoral researchers, and a target of 40-60% female participation among the funded teams will promote gender equality. The tripartite US-Ireland consortium also ensures meaningful cross-border collaboration between teams on the island of Ireland, North and South, thereby working towards the twin goals of building prosperity and an all-island economy and continuing the work of peace and reconciliation between the two jurisdictions.Technical SummaryThis collaborative project, supported by the Solid State and Materials Chemistry program and the Condensed Matter Physics program, both in the Division of Materials Research, sets out routes to harness the switchable electronic spin states that occur in certain paramagnetic transition metal complexes for development of a new class of magnetoelectric materials. The target compounds are spin crossover metal-organics which can change their internal arrangement of electrons in d-orbitals from paired to unpaired with heat, photoexcitation, pressure/strain or electric and magnetic fields. The project examines the interplay between changes in electric, magnetic and structural properties that accompany the spin state switching under a range of perturbations. Routes to robust nanofabrication of the crystalline metal-organics are also explored. Four interdisciplinary sub-projects are investigated: (1) Optimization of synthetic routes to ensure (i) crystallization in a polar ferroelectric space group and (ii) retention of thermal spin state switching; (2) Characterization of (i) the spin state and (ii) the ferroelectric domain structure; (3) Potential for magnetic, electric, optical and strain switching of spin state and electric polarization; and (4) Nanofabrication of the metal-organics from crystals into arrays on thin films. The focus on molecule-based metal-organics with soft lattices offers an alternative and advantageous pathway towards materials with magnetic and electric polarization responses that are readily switchable at room temperature, with future potential for ultra-fast, low energy memory applications.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.