报告主题：Spin- and Orbitronics in magnetic systems going beyond s-wave
主讲嘉宾：Mathias Kläui欧洲科学院院士 美因茨大学物理系
时间：4月18日 （周五）下午 14:00
地点：教2-327会议室
主办单位：南京邮电大学理学院
邀请人：吕衍凤教授
报告内容：
Novel spintronic devices can play a role in the quest for GreenIT if they are stable and can transport and manipulate angular momentum with low power. Conventional devices based on ferromagnetism that has an s-wave spin symmetry have been proposed, where switching by energy-efficient approaches is used to manipulate topological spin structures in 2D and 3D.
We combine the enhanced stability of topological states due to chiral interactions with enhanced manipulation efficiency using novel spin orbit torques. Using the orbital degree of freedom increases the switching efficiency drastically further.
Enhanced stability is found going beyond s-wave magnets to systems with compensated magnetic moments that are insensitive to stray fields and also exhibit ultra-fast dynamics. Starting with synthetic antiferromagnets we demonstrate new meron topological spin structures and enhanced topological spin structure dynamics.
Particular symmetries enable even in systems with fully compensated magnetic order spin-polarized Fermi surfaces. This includes non-collinear antiferromagnets that can exhibit p-wave spin symmetry as well as collinear d-wave (e.g. RuO2) and g-wave altermagnets (e.g. CrSb) where we reveal the spin-split bands. In the altermagnet hematite that can host antiferromagnetic antiskyrmions we find that ultra-low damping enables long distance spin transport and the altermagnetic nature manifests itself in the crystal Hall effect. Using d-wave altermagnetic orthoferrites, we can probe the spin split magnonic bands leading to non-reciprocal spin transport.
2D materials that can exhibit these symmetries are particularly exciting as heterostructures of differently ordered magnetic and non-magnetic materials with atomically flat interfaces lead to enhanced coupling effects.
Finally, such systems are not only of interest from a fundamental science point of view but their stability, efficient manipulation and fast dynamics also hold prospects for a range of applications such as memory and unconventional computing.
报告人简介：
Mathias Kläui教授，2003年博士毕业于英国剑桥大学物理专业，随后在瑞士IBM苏黎世实验室开展博士后研究。2003-2008年，担任德国康斯坦茨大学担任资深科学家。2010-2011年，担任瑞士联邦理工学院副教授。2011年至今，担任美因茨约翰内斯古腾堡大学正教授。2012年至今，担任美因茨卓越材料科学研究生院院长。2014年，当选为英国物理学会（IOP）会士。2014-2020年，担任古腾堡青年研究人员委员会执行委员会成员，并于2014-2017年担任创始主任。2017年至今，担任挪威科技大学特隆赫姆分校量子自旋电子学中心的名誉教授。2020年，当选为美国物理学会（APS）会士，同时当选为欧洲科学院院士。2022年，当选为电气与电子工程师协会（IEEE）会士。