Chiral Spin Textures in Magnetic Nanostructures

磁性纳米结构中的手性自旋纹理

• 批准号: 2005108
• 负责人: Kai Liu
• 金额: $ 51.98万
• 依托单位: Georgetown University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-08-01 至 2024-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2005108&HistoricalAwards=false
• 关键词: Chiral; Spin; Textures; Magnetic; Nanostructures

Nontechnical Abstract:Magnetic moments in magnets can form various configurations known as spin textures, such as domain walls where the moments form a winding configuration connecting adjacent domains with different magnetization directions. Usually, the rotational sense of the moments in spin textures is expected to be achiral, where the left- and right-handed rotations are equally possible. In certain magnetic thin films, the broken inversion symmetry of atomic structure at the interface between magnetic and heavy metal layers leads to an interfacial effect which lifts the chiral degeneracy and stabilizes chiral spin structures such as spin spirals, chiral domain walls or magnetic skyrmions. These chiral spin textures exhibit a preferred handedness and fascinating topological characteristics. Their extraordinary properties provide new insights into fundamental problems of magnetism and exciting potentials for novel magnetic technologies. This project aims at significantly advancing the field by unlocking a number of degrees of freedom for a better understanding and control of such spin textures. Several novel spin textures are investigated, including exotic types of skyrmions and chiral domain walls in 2-dimensional thin films and topological spin textures such as Mobius bands in 3-dimensional magnetic structures. They have the potential to fundamentally transform the energy landscape for future information storage. This project provides valuable training opportunities for students in university as well as national laboratory and other facilities. The principal investigator actively engages in a variety of efforts to broaden participation from underrepresented groups through course offering, public lectures, exchange visits, and professional conference organization.Technical Abstract:Chiral spin textures are investigated to demonstrate a number of new degrees of freedom to better control them, including antiskyrmion Hall angle, topological number, chemisorbed species, and 3-dimensional topological configuration. Anisotropic Dzyaloshinskii-Moriya interaction is utilized to stabilize antiskyrmions in magnetic thin films. The antiskyrmion Hall angle is explored for controlling skyrmion trajectory or topological sorting, which can be potentially used for designing complex skyrmionics devices. High winding number skyrmions are demonstrated, which unlocks the topological number as a new degree of freedom that may support novel topological functionalities in logic devices. Effects of chemisorbed species under vacuum onto ferromagnet films are studied to induce chiral domain walls and enable direct writing of skyrmions without magnetic or electric fields. Chemisorptions of low atomic number atoms and organic molecules are studied to induce reversible switching of magnetic chirality and tuning of perpendicular magnetic anisotropy. Novel types of 3-dimensional topological spin textures such as Mobius bands are fabricated and their topological characters are investigated. These novel spin textures offer new mechanisms for robust and low dissipation information storage, which is well aligned with grand challenges for future nanoelectronics. This project includes a wide variety of efforts to broaden participation from underrepresented groups. Students involved receive excellent exposure to research experience in academia, government laboratory and other research facilities.This DMR grant supports research on chiral spin structure in magnetic nanoparticles with funding from the Condensed Matter Physics (CMP) and the Electronic and Photonic Materials (EPM) Programs in the Division of Materials Research of the Mathematical and Physical Sciences Directorate.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.

非技术摘要：磁铁中的磁矩可以形成各种称为旋转纹理的构型，例如域壁，其中矩形成绕组构型，与不同的磁化方向连接相邻域的绕组构型。通常，旋转纹理中矩的旋转意义预计将是恰当的，其中左手和右旋转是同样可能的。在某些磁性薄膜中，在磁性和重金属层之间界面处的原子结构的倒置对称性导致界面效应，从而提高了手性退化，并稳定了手性旋转结构，例如旋转螺旋，手性结构域或磁性弹性。这些手性旋转纹理表现出优先的手式和引人入胜的拓扑特征。它们的非凡特性为磁性的基本问题和令人兴奋的新型磁性技术提供了新的见解。 该项目的目的是通过解锁多个自由度，以更好地理解和控制此类旋转纹理，从而大大推进该领域。研究了几种新型的自旋纹理，包括二维薄膜中的Skyrmions和手性域壁的外来类型，以及三维磁性结构中的Mobius带等拓扑自旋纹理。他们有可能从根本上改变能源格局以进行未来的信息存储。该项目为大学的学生以及国家实验室和其他设施提供了宝贵的培训机会。首席调查员积极从事各种努力，以通过课程提供，公开讲座，交流访问和专业会议组织来扩大代表性不足的群体的参与。技术摘要：手学旋转质地，以证明许多新的自由度以更好地自由以更好地提高更好的自由度控制它们，包括反震颤厅的角度，拓扑数，化学吸附物种和3维拓扑结构。各向异性的dzyaloshinskii-moriya相互作用用于稳定磁性薄膜中的抗微米。探索了Antiskyrmion Hall角度用于控制天际轨迹或拓扑分类，这可能用于设计复杂的Skyyrmionics设备。展示了高缠绕数的天空，这将拓扑数作为一种新的自由度解锁，可以支持逻辑设备中的新拓扑功能。研究了真空下化学吸附物种对铁磁铁膜的影响，以诱导手性域壁，并能够直接写入没有磁性或电场的天空。研究低原子数原子和有机分子的化学分化，以诱导磁性手性的可逆切换和垂直磁各向异性的调整。新型的三维拓扑旋转纹理（例如莫比乌斯频带）的新型类型被制造，并研究了它们的拓扑特征。这些新颖的旋转纹理为稳健和低耗散信息存储提供了新的机制，这与未来纳米电子学面临的巨大挑战相符。该项目包括各种各样的努力，以扩大代表性不足的群体的参与。参与的学生在学术界，政府实验室和其他研究设施中获得了极大的接触。该DMR拨款通过凝聚态物理学（CMP）的资金以及电子和光子材料（EPM）计划的资金支持有关磁性纳米颗粒手性旋转结构的研究。该奖项在数学和物理科学局的材料研究部中。该奖项反映了NSF的法定任务，并使用基金会的知识分子优点和更广泛的影响审查标准，被认为值得通过评估。

项目成果

Room‐Temperature Magnetic Skyrmions and Large Topological Hall Effect in Chromium Telluride Engineered by Self‐Intercalation

• DOI: 10.1002/adma.202205967
• 发表时间: 2022-10
• 期刊: Advanced Materials
• 影响因子: 29.4
• 作者: Chen-hui Zhang;Chen Liu;Junwei Zhang;Youyou Yuan;Y. Wen;Yan Li;D. Zheng;Qiang Zhang;Z. Hou;G. Yin;Kai Liu;Yong Peng;Xixiang Zhang

Chirality-induced zigzag domain wall in in-plane magnetized ultrathin films

• DOI: 10.1116/6.0001170
• 发表时间: 2021-08
• 作者: Gong Chen;M. Robertson;H. Kwon;C. Won;A. Schmid;Kai Liu

A Van der Waals Interface Hosting Two Groups of Magnetic Skyrmions

• DOI: 10.1002/adma.202110583
• 发表时间: 2021-12
• 期刊: Advanced Materials
• 影响因子: 29.4
• 作者: Yingying Wu;Brian A. Francisco;Zhijie Chen;Wei Wang;Yu Zhang;C. Wan;Xiufeng Han;H. Chi;Yasen Hou;A. Lodesani;G. Yin;Kai Liu;Yong-Tao Cui;Kang Wang;J. Moodera

Antiferromagnet Thickness Dependence and Rotatable Spins in Exchange Biased CoO/Fe Films

• DOI: 10.1016/j.jmmm.2022.169898
• 发表时间: 2022-09
• 期刊: Journal of Magnetism and Magnetic Materials
• 影响因子: 2.7
• 作者: P. Greene;Yong Hu;Z. Qiu;Kai Liu

High‐Efficiency Magnon‐Mediated Magnetization Switching in All‐Oxide Heterostructures with Perpendicular Magnetic Anisotropy

具有垂直磁各向异性的全氧化物异质结构中的高效率磁振子介导的磁化切换

• DOI: 10.1002/adma.202203038
• 发表时间: 2022
• 期刊: Advanced Materials
• 影响因子: 29.4
• 作者: Zheng, Dongxing;Lan, Jin;Fang, Bin;Li, Yan;Liu, Chen;Ledesma‐Martin, J. Omar;Wen, Yan;Li, Peng;Zhang, Chenhui;Ma, Yinchang
• 通讯作者: Ma, Yinchang