Axel Hoffman – Rh, Pd, Ir, Pt: What makes them special for spintronics?

ABSTRACT

Spintronics is the concept of using magnetic spin degrees of freedom for encoding information, while using electronic charge currents for manipulating and detecting magnetic states [1].  This approach is very well established for non-volatile memories, but increasingly also gains attention for novel computational paradigms, such as neuromorphic [2] or quantum computing [3].  One of the key physical phenomena are spin-orbit coupling effects, which can provide strong magnetic anisotropies and enable charge-to-spin current conversion [4].  Towards this end, Rh, Pd, Ir and Pt are of special interest, since their partially filled d-electronic shells and their relatively heavy atomic nuclei give rise to very strong spin-orbit coupling effects.  I will illustrate with some specific examples [5,6] how the alloys and heterostructures incorporating these elements have relevance for modern spintronics developments. 

This work was supported as part of Quantum Materials for Energy Efficient Neuromorphic Computing (Q-MEEN-C), an Energy Frontier Research Center funded by the US Department of Energy, Office of Science, Basic Energy Sciences under Award No. DE-SC0019273. 

Slide deck: Axel Hoffman_Johnson Matthey 2023

References 

[1] A. Hoffmann and S. D. Bader, Phys. Rev. Appl. 4, 047001 (2015). 

[2] A. Hoffmann, et al., APL Mater. 10, 070904 (2022). 

[3] Y. Li, et al., 2022 IEEE Intern. Electr. Devices Meeting, 16.6.1 (2022). 

[4] Q. Shao, et al., IEEE Trans. Magn. 57, 800439 (2021). 

[5] W. Jiang, et al., Science 349, 283 (2015). 

[5] J. Gibbons, et al., Phys. Rev. Appl. 18, 024075 (2022). 

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BIOGRAPHY

Department of Materials Science and Engineering and Materials Research Laboratory,  
University of Illinois Urbana-Champaign, Urbana, IL 61801, U.S.A. 

Axel Hoffmann has obtained his Diploma degree in physics from the RWTH Aachen in 1994 and his PhD degree in physics from the University of California – San Diego in 1999. Subsequently he worked at the Los Alamos National Laboratory as a postdoctoral fellow. In 2001 he joined the Argonne National Laboratory as a staff scientist, and became in 2014 the Senior Group Leader of the Magnetic Thin Film Group within the Materials Science Division. In 2019 he joined the Department of Materials Science an Engineering at the University of Illinois at Urbana-Champaign as a Full Professor. His research interests encompass a wide variety of magnetism related subjects, including basic properties of magnetic heterostructures, spin-transport in novel geometries, and biomedical applications of magnetism. His main research focus has recently been on pure spin currents investigated by magnetotransport and magnetization dynamic measurements. He has more than 200 publications, five book chapters, four magnetism-related U.S. patents, and edited two books. He is an Associate Editor for the Journal of Applied Physics and a fellow of the American Physical Society, American Vacuum Society, and IEEE. His awards include Distinguished Lecturer for the IEEE Magnetics Society in 2011, Outstanding Researcher Award by the Prairie Section of the American Vacuum Society 2015, President’s International Fellowship from the Chinese Academy of Sciences in 2016, Highly Cited Researcher by the Web of Science Group in 2019–2022, and the David Adler Lectureship Award in the Field of Materials Physics from the American Physical Society in 2022.