Materials World Network: Half Metallic Transport in Chemically Complex Systems

该奖项支持来自俄亥俄州州立大学和德国德累斯顿莱布尼茨研究所（IFW）的国际合作研究团队实现和理解Heusler化合物和双钙钛矿中的半金属性（即导电电子的100%自旋极化）。这两类复杂材料包含绝大多数具有高居里温度的半金属化合物，这些化合物有望在室温下实现高度自旋极化传输。为了推进我们的基本理解以及这两个家庭的自旋极化运输的技术承诺，这种伙伴关系汇集了互补的专业知识，在高质量的外延膜沉积的复杂材料和自旋极化测量在俄亥俄州州立大学和单晶生长这些材料使用国家的最先进的设施在莱布尼茨研究所在德国。尽管它们有希望，但它们的化学复杂性和对缺陷和反位无序的敏感性限制了在原型和真实的器件中对Heusler化合物和双钙钛矿的研究。基础物理学的许多方面仍然没有得到很好的理解，这也阻碍了进展。该项目有两个目标：（1）使用离轴磁控真空溅射存款具有高居里温度的Heusler化合物的高质量半金属外延膜和磁性隧道结，并结合其结构、化学、磁性、电子、自旋极化和元素特定磁矩的表征;（2）生长半金属双钙钛矿的单晶。这种晶体的可用性将使其内在的自旋极化和磁输运性质的调查。这些材料的真正前景只能通过将内在特性与源自结构和化学不均匀性的外在贡献分开来评估。该项目的目标是建立将半金属材料纳入自旋电子器件所需的科学和技术基础。这一国际合作结合了实现半金属铁磁体用于自旋电子学的承诺所需的集体和互补专业知识。室温应用的高自旋极化铁磁体的可用性将建立一个具有革命性计算潜力的基础。此外，这一努力将加强美国和德国社区之间的联系，这将加强双方合作机构的研究基础设施。最后，科学的挑战，以及研究计划的跨学科和国际性将为学生研究人员和初级科学家提供良好的培训。

This award supports an international collaborative research team from the Ohio State University and the Leibniz Institute (IFW) in Dresden, Germany to realize and understand half-metallicity (i.e. 100% spin polarization of conduction electrons) in Heusler compounds and double perovskites. These two families of complex materials contain the vast majority of half-metallic compounds with high Curie temperatures that hold the promise of highly spin polarized transport at room temperature. To advance both our fundamental understanding as well as the technological promise of spin-polarized transport in these two families, this partnership brings together complementary expertise in high-quality epitaxial film deposition of complex materials and spin polarization measurements at the Ohio State University and single-crystal growth of these materials using the state-of-the-art facilities at the Leibniz Institute in Germany. Despite their promise, their chemical complexity and sensitivity to defects and antisite disorder has limited studies of Heusler compounds and double perovskites in prototype and real devices. Progress is also hindered by the fact that many aspects of the fundamental physics are still not well understood. This project has two aims: (1) deposit high quality, half-metallic epitaxial films and magnetic tunnel junctions of Heusler compounds with high Curie temperatures using off-axis ultrahigh vacuum sputtering, coupled with characterization of their structural, chemical, magnetic, electronic, spin polarization, and element-specific magnetic moments; (2) grow single crystals of half-metallic double perovskites. Availability of such crystals will enable investigations of their intrinsic spin polarization and magnetotransport properties. The true promise of these materials can only be assessed by separating intrinsic properties from extrinsic contributions originating from structural and chemical inhomogeneity. The goal of this project is to establish the scientific and technical foundations needed to incorporate half metallic materials in spintronic devices.This international collaboration combines the collective and complementary expertise needed to realize the promise of half-metallic ferromagnets for use in spintronics. The availability of highly spin-polarized ferromagnets for room temperature applications will establish a groundwork that has the potential to revolutionize computing. In addition, this effort will strengthen the ties between US and German communities that will enhance the research infrastructure of both partner institutions. Finally, the scientific challenges, as well as the interdisciplinary and international nature of the research program will provide excellent training for the student researchers and junior scientists.