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：磁体中的磁矩可以形成称为自旋纹理的各种配置，例如畴壁，其中磁矩形成连接具有不同磁化方向的相邻畴的绕组配置。通常情况下，自旋纹理中的旋转方向的力矩被认为是非手性的，其中左手和右手旋转同样可能。在某些磁性薄膜中，在磁性层和重金属层之间的界面处原子结构的反转对称性的破缺导致界面效应，该界面效应提升手性简并稳定手性自旋结构，例如自旋螺旋、手性畴壁或磁性skyrmion。这些手征自旋织构表现出一种偏好的旋向性和迷人的拓扑特征。它们非凡的性质为磁性的基本问题提供了新的见解，并为新的磁性技术提供了潜在的激励。 该项目旨在通过解锁多个自由度以更好地理解和控制此类自旋纹理来显著推进该领域。几种新的自旋织构的研究，包括奇异类型的skyrmions和手征畴壁在2维薄膜和拓扑自旋织构，如Mobius带在3维磁结构。它们有可能从根本上改变未来信息存储的能源格局。该项目为大学生以及国家实验室和其他设施提供了宝贵的培训机会。主要研究者积极参与各种努力，以扩大参与，从代表性不足的群体，通过课程提供，公开讲座，交流访问，和专业会议organization.Technical摘要：手性自旋纹理进行了调查，以证明一些新的自由度，以更好地控制他们，包括antiskyrmion霍尔角，拓扑数，化学吸附的物种，和三维拓扑构型。利用各向异性的Dzyaloshinskiii-Moriya相互作用稳定磁性薄膜中的反回旋子。反skyrmion霍尔角被探索用于控制skyrmion轨迹或拓扑排序，这可以潜在地用于设计复杂的skyrmionics器件。高缠绕数的skyrmions被证明，它解锁的拓扑数作为一个新的自由度，可能会支持新的拓扑功能的逻辑器件。研究了真空下化学吸附物种对铁磁薄膜的影响，以诱导手征畴壁，从而在没有磁场或电场的情况下直接写入Skyrmions。研究了低原子序数原子和有机分子的化学吸附，以诱导磁手性的可逆转换和垂直磁各向异性的调谐。制备了新型的三维拓扑自旋织构，如Mobius带，并研究了它们的拓扑性质。这些新的自旋纹理提供了新的机制，强大的和低耗散的信息存储，这是很好地与未来纳米电子学的巨大挑战。该项目包括各种努力，以扩大代表性不足群体的参与。参与的学生获得了良好的学术研究经验，这项DMR拨款支持在凝聚态物理学（CMP）和电子与光子材料（MEMS）的资助下，对磁性纳米粒子中的手性自旋结构进行研究。该奖项反映了NSF的法定使命，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。

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

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

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