时间:2017年12月15日  上午10点

地点：新主楼F706.

摘要：Nanomaterials Playground: Magnetic Skyrmions, Magneto-Ionics and Metal Foams      

Kai Liu    

Physics Department, University of California, Davis, CA 95616    

Nanomaterials offer an exciting platform to address grand challenges in the post-Moore’s law era. In this talk I will illustrate some of our current efforts. For example, in recently discovered magnetic skyrmions, mostly at low temperatures, the unique spin texture and the topologically protected quantum state offer great potentials for low dissipation magnetic information storage. We have demonstrated the realization of artificial Bloch skyrmion lattices, as well as planar skyrmion lattices, in their ground state at room temperature [1]. In a second area, we have demonstrated effective magneto-ionic manipulation of metal/oxide interfaces due to a redox-driven oxygen migration, manifested through the interface-sensitive exchange bias effect [2] and controllable under an electric field [3]. Similar effects are also found in getter-metal/perovskites, where the ferromagnetism is sensitively moderated by O-migration [4]. More recently, we have achieved ultra-lightweight palladium nanowire foams that exhibit highly attractive characteristics for hydrogen storage [5].    

1. Nature Communications 6, 8462, (2015).    

2. Nature Communications 7, 11050 (2016).    

3. Nature Communications 7, 12264 (2016).    

4. Appl. Phys. Lett. 108, 082405 (2016).    

5. Chem. Mater. DOI:10.1021/acs.chemmater.7b03978 (2017).  

简介：

Prof. Kai Liu received his Ph.D. degree from the John Hopkins University in 1998. In 2001, he jointed into the University of California, Davis as an assistant professor. In 2008, he became the full professor. Until now, he has received lots of honors, including IEEE Fellow and APS Fellow, etc. His research interest is in experimental studies of nanostructured materials for nanomagnetism, spin-transport, and advanced energy explorations. Due to their intricate nanostructures, extremely small length scales, rich surfaces and interfaces, low dimensionality, and interplay among constituents, nanostructured materials often exhibit new and enhanced properties over their bulk counterparts. Additionally, these novel properties can be tailored through extra degrees of freedom, such as structure and material. Professor Liu is particularly interested in magnetic nanostructures where the electron spin coherence may be preserved and exploited, providing a spin-based vision for electronics of the future. This is of critical importance as downscaling of CMOS-based devices face huge uncertainties regarding power consumption and dissipation, resulting in a catastrophic power crisis that has stalled progress across all scales. Spin-based applications represent potentially paradigm-shifting innovations and transformative opportunities that can address the grand challenges of our time.