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

该合作项目涉及美国、爱尔兰共和国和北爱尔兰的合作伙伴，重点是实现一种新型材料的分子水平控制，这种材料具有在环境温度下易于切换的电和磁特性。该项目由材料研究部固态与材料化学项目和凝聚态物理项目支持。特别重要的是，通过选择特定的分子构建块来调节不同材料特性之间的耦合的可能性，这样就有可能切换，例如，用外部刺激来切换磁性状态，而通常只会切换电性能，反之亦然。这种多功能行为可能为超低能耗的超快速内存存储应用铺平道路，从而解决电子设备持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，以及纳米级器件结构的制造路线。因此，预计将在几个层面产生影响，主要是在变革性基础科学方面，但也会增加对分子设计原理的理解，从而为21世纪带来新技术。这个高度跨学科和跨国的联盟为早期的博士和博士后研究人员提供了良好的培训和流动机会，并且在资助团队中女性参与的目标为40-60%，这将促进性别平等。三方美国-爱尔兰联盟还确保爱尔兰岛南北团队之间有意义的跨境合作，从而朝着建设繁荣和全岛经济的双重目标努力，并继续在两个司法管辖区之间进行和平与和解的工作。该合作项目由材料研究部的固态与材料化学项目和凝聚态物理项目支持，为利用某些顺磁性过渡金属配合物中发生的可切换电子自旋态来开发一类新的磁电材料制定了路线。目标化合物是自旋交叉金属有机物，它们可以在热、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，从成对变为不成对。该项目研究了在一系列扰动下自旋状态切换所伴随的电、磁和结构特性变化之间的相互作用。还探讨了坚固的结晶金属有机物的纳米加工路线。研究了四个跨学科子项目：(1)优化合成路线，以确保(i)在极性铁电空间群中结晶和（ii）保留热自旋态开关；(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、光和应变切换潜力；(4)将金属有机物从晶体纳米加工成薄膜阵列。对具有软晶格的分子基金属有机物的关注为具有磁和电极化响应的材料提供了一种替代和有利的途径，这种材料在室温下易于切换，具有超快速，低能量存储应用的未来潜力。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 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.