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 Axel Hoffmann
Axel Hoffmann

Axel Hoffmann

Professor
  • Materials Science and Engineering
(217) 300-4374
1021 Superconductivity Center

Education

  • Ph.D., Physics, University of California – San Diego, 1999
  • Diplom, Physics, RWTH Aachen, Germany, 1994

Biography

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. In 2019 he joined the Department of Materials Science an Engineering at the University of Illinois at Urbana-Champaign as a Founder Professor. His research interests encompass a wide variety of magnetism related subjects, including basic properties of magnetic heterostructures, spin-transport in novel geometries, and magnetization dynamics. He is an Associate Editor for the Journal of Applied Physics and a fellow of the American Physical Society, American Vacuum Society, and IEEE.

Academic Positions

  • Professor, University of Illinois at Urbana-Champaign, Materials Science and Engineering, 2019–present

Other Professional Employment

  • Postdoctoral Fellow, Los Alamos National Laboratory, Los Almost, NM, 1999–2001
  • Assistant Materials Scientist, Argonne National Laboratory, Lemont, IL, 2001–2005
  • Materials Scientist, Argonne National Laboratory, Lemont, IL, 2005–2014
  • Senior Group Leader, Argonne National Laboratory, Lemont, IL, 2014–2019

Major Consulting Activities

  • Associate Editor, Journal of Applied Physics, American Institute or Physics, 2009–present

Books Edited or Co-Edited (Original Editions)

  • Topology in Magnetism Edited by J. Zhang, V. Cros, and A. Hoffmann, (Springer, New York, September 2018).
  • Recent Advances in Magnetic Insulators – From Spintronics to Microwave Applications Edited by M. Wu and A. Hoffmann, Solid State Physics, vol. 64 (Academic Press, Oxford, December 2013).

Chapters in Books

  • Spin-Orbit Torques W. Zhang, M. B. Jungfleisch, R. Winkler, and A. Hoffmann, In: Spin Physics in Semiconductors, 2nd edition, edited by Michael I. Dyakonov (Springer, New York, 2017), p. 355–385.

Selected Articles in Journals

  • Magnetostatic spin-waves in an yttrium iron garnet thin film: Comparison between theory and experiment for arbitrary field directions J. Lim, W. Bang, J. Trossman, D. Amanov, C. C. Tsai, M. Jungfleisch, A. Hoffmann, and J. B. Ketterson, Journal of Applied Physics 126, 243906 (2019).
  • Spin-wave frequency division multiplexing in an yttrium iron garnet microstripe magnetized by inhomogeneous field Z. Zhang, M. Vogel, J. Holanda, M. B. Jungfleisch, C. Liu, Y. Li, J. E. Pearson, R. Divan, W. Zhang, A. Hoffmann, Y. Nie, and V. Novosad, Applied Physics Letters 115, 232402 (2019).
  • Generation and Hall effect of skyrmions enabled via using nonmagnetic constriction Z. Wang, X. Zhang, J. Xia, L. Zhao, K. Wu, G. Yu, K. L. Wang, X. Liu, S. G. E. te Velthuis, A. Hoffmann, Y. Zhou, and W. Jiang, Physical Review B 100, 184426 (2019).
  • Tuning edge-localized spin waves in magnetic microstripes by proximate magnetic structures Z. Zhang, M. Vogel, M. B. Jungfleisch, A. Hoffmann, Y. Nie, and V. Novosad, Physical Review B 100, 174434 (2019).
  • Ferromagnetic resonance spectra of permalloy nano-ellipses as building blocks for complex magnonic lattices W. Bang, F. Montoncello, M. T. Kaffash, A. Hoffmann, J. B. Ketterson, and M. B. Jungfleisch, Journal of Applied Physics 126, 203902 (2019).
  • Strong Coupling between Magnons and Microwave Photons in On-Chip Ferromagnet-Superconducting Thin-Film Devices Y. Li, T. Polakovic, Y.-L. Wei, J. Xu, S. Lendinez, Z. Zhang, J. Ding, T. Khaire, H. Saglam, R. Divan, J. Pearson, W.-K. Kwok, Z. Xiao, V. Novosad, A. Hoffmann, and W. Zhang, Physical Review Letters 123, 107701 (2019).
  • Magnetization switching utilizing topological surface states P. Li, J. Kally, S. S.-L. Zhang, T. Pillsbury, J. Ding, G. Csaba, J. Ding, J. S. Jiang, Y. Liu, R. Sinclair, C. Bi, A. DeMann, G. Rimal, W. Zhang, S. B. Field, J. Tang, W. Wang, O. G. Heinonen, V. Novosad, A. Hoffmann, N. Samarth, and M. Wu, Science Advances 5, eaaw3415 (2019).
  • Controlled interconversion of quantized spin wave modes via local magnetic fields Z. Zhang, M. Vogel, J. Holanda, J. Ding, M. B. Jungfleisch, Y. Li, J. E. Pearson, R. Divan, W. Zhang, A. Hoffmann, Y. Nie, and V. Novosad, Physical Review B 100, 014429 (2019).
  • Spin Seebeck effect in insulating SrFeO3-δ films D. Hong, C. Liu, J. E. Pearson, A. Hoffmann, D. D. Fong, and A. Bhattacharya, Applied Physics Letters 114, 242403 (2019).
  • Giant anisotropy of Gilbert damping up to 300% in epitaxial CoFe films Y. Li, F. Zeng, S. Zhang, H. Shin, H. Saglam, V. Karakas, O. Ozatay, J. E. Pearson, O. G. Heinonen, Y. Wu, A. Hoffmann, and W. Zhang, Physical Review Letters 122, 117203 (2019).
  • Simultaneous Optical and Electrical Spin-Torque Magnetometry with Phase-Sensitive Detection of Spin Precession Y. Li, H. Saglam, Z. Zhang, R. Bidthanapally, Y. Xiong, J. E. Pearson, V. Novosad, H. Qu, G. Srinivasan, A. Hoffmann, and W. Zhang, Physical Review Applied 11, 034047 (2019).
  • Quantifying chiral exchange interaction for Néel-type skyrmions via Lorentz transmission electron microscopy W. Jiang, S. Zhang, X. Wang, C. Phatak, Q. Wang, W. Zhang, M. B. Jungfleisch, J. E. Pearson, Y. Liu, J. Zang, X. Cheng, A. Petford-Long, A. Hoffmann, and S. G. E. te Velthuis, Physical Review B 99, 104402 (2019).
  • Direct detection of multiple backward volume modes in yttrium iron garnet at micron scale wavelengths J. Lim, W. Bang, J. Trossman, A. Kreisel, M. B. Jungfleisch, A. Hoffmann, C. C. Tsai, and J. B. Ketterson Physical Review B 99, 014435 (2019).
  • Angular-dependent spin dynamics of a triad of permalloy macrospins W. Bang, F. Montoncello, M. B. Jungfleisch, A. Hoffmann, L. Giovannini, and J. B. Ketterson, Physical Review B 99, 014415 (2019).
  • Independence of spin-orbit torques from the exchange bias direction in Ni81Fe19/IrMn bilayers H. Saglam, J. C. Rojas-Sanchez, S. Petit, M. Hehn, W. Zhang, J. E. Pearson, S. Mangin, and A. Hoffmann, Physical Review B 98, 094407 (2018).
  • Control of Terahertz Emission by Ultrafast Spin-Charge Current Conversion at Rashba Interfaces M. B. Jungfleisch, Q. Zhang, W. Zhang, J. E. Pearson, R. D. Schaller, H. Wen, and A. Hoffmann, Physical Review Letters 120, 207207 (2018).
  • Spin transport and spin torque in antiferromagnetic devices J. Železný, P. Wadley, K. Olenik, A. Hoffmann, and H. Ohno, Nature Physics 14, 220 (2018).
  • Perspectives of antiferromagnetic spintronics M. B. Jungfleisch, W. Zhang, and A. Hoffmann, Physics Letters A 382, 865 (2018).
  • High-Frequency Dynamics Modulated by Collective Magnetizatio Reversal in Artificial Spin Ice M. B. Jungfleisch, J. Sklenar, J. Ding, J. Park, J. E. Pearson, V. Novosad, P. Schiffer, and A. Hoffmann, Physical Review Applied 8, 064026 (2017).
  • Determination of spin relaxation times in heavy metals via 2nd harmonic spin injection magnetoresistance C. Fang, C. H. Wan, B. S. Yang, J. Y. Qin, B. S. Tao, H. Wu, X. Zhang, X. F. Han, A. Hoffmann, X. M. Liu, and Z. M. Jin, Physical Review B 98, 134421 (2017).
  • Magentization reversal in Py/Gd heterostructures P. N. Lapa, J. Ding, J. E. Pearson, V. Novosad, J. S. Jiang, and A. Hoffmann, Physical Review B 96, 024418 (2017).
  • Unidirectional spin-torque driven magnetization dynamics J. Sklenar, W. Zhang, M. B. Jungfleisch, H. Saglam, S. Grudichak, W. Jiang, J. E. Pearson, J. B. Ketterson, and A. Hoffmann, Physical Review B 95, 224431 (2017).
  • Interface-induced phenomena in magnetism F. Hellman, A. Hoffmann, Y. Tserkovnyak, G. S. D. Beach, E. E. Fullerton, C. Leighton, A. H. MacDonald, D. C. Ralph, D. A. Arena, H. A. Dürr, P. Fischer, J. Grollier, J. P. Heremans, T. Jungwirth, A. V. Kimel, B. Koopmans, I. N. Krivorotov, S. J. May, A. K. Petford-Long, J. M. Rondinelli, N. Samarth, I. K. Schuller, A. N. Slavin, M. D. Stiles, O. Tchernyshov, and A. Thiaville, Review of Modern Physics 89, 025006 (2017).
  • Direct observation of the skyrmion Hall effect W. Jiang, X. Zhang, G. Yu, W. Zhang, M. B. Jungfleisch, J. E. Pearson, O. Heinonen, K. L. Wang, Y. Zhou, A. Hoffmann, and S. G. E. te Velthuis, Nature Physics 13, 162 (2017).
  • Insulating Nanomagnets Driven by Spin Torque M. B. Jungfleisch, J. Ding, H. Saglam, W. Zhang, W. Jiang, J. E. Pearson, V. Novosad, and A. Hoffmann, Nano Letters 17, 8 (2017).
  • Spin transport through the metallic antiferromagnet FeMn H. Saglam, W. Zhang, M. B. Jungfleisch, J. Sklenar, W. Jiang, J. E. Pearson, J. B. Ketterson, and A. Hoffmann, Physical Review B 94, 140412(R) (2016).
  • Interface-driven spin-torque ferromagnetic resonance by Rashba coupling at the interface between nonmagnetic materials M. B. Jungfleisch, W. Zhang, J. Sklenar, W. Jiang, J. E. Pearson, J. B. Ketterson, and A. Hoffmann, Physical Review B 93, 224419 (2016).
  • Research Update: Spin transfer torques in permalloy on monolayer MoS2 W. Zhang, J. Sklenar, B. Hsu, W. Jiang, M. B. Jungfleisch, J. Xiao, F. Y. Fradin, Y. Liu, J. E. Pearson, J. B. Ketterson, Z. Yang, and A. Hoffmann, APL Materials 4, 032302 (2016).
  • Antiferromagnetic Spin Seebeck Effect S. Wu, W. Zhang, A. KC, P. Borisov, J. E. Pearson, J. S. Jiang, D. Lederman, A. Hoffmann, and A. Bhattacharya, Physical Review Letters 116, 097204 (2016).
  • Large spin-wave bullet in a ferrimagnetic insulator driven by spin Hall effect M. B. Jungfleisch, W. Zhang, J. Sklenar, J. Ding, W. Jiang, H. Chang, F. Y. Fradin, J. E. Pearson, J. B. Ketterson, V. Novosad, M. Wu, and A. Hoffmann, Physical Review Letters 116, 057601 (2016).
  • Epitaxial patterning of nanometer-thick Y3Fe5O12 films with low magnetic damping S. Li, W. Zhang, J. Ding, J. E. Pearson, V. Novosad, and A. Hoffmann, Nanoscale 8, 388 (2016).
  • Driving and detecting ferromagnetic resonance in insulators with the spin Hall effect J. Sklenar, W. Zhang, M. B. Jungfleisch, W. Jiang, H. Chang, J. E. Pearson, M. Wu, J. B. Ketterson, and A. Hoffmann, Physical Review B 92, 174406 (2015).
  • All-electrical manipulation of magnetization dynamics in a ferromagnet by antiferromagnets with anisotropic spin Hall effects W. Zhang, M. B. Jungfleisch, F. Freimuth, W. Jiang, J. Sklenar, J. E. Pearson, J. B. Ketterson, Y. Mokrousov, and A. Hoffmann, Physical Review B 92, 144005 (2015).
  • Opportunities at the Frontiers of Spintronics A. Hoffmann and S. D. Bader, Physical Review Applied 4, 047001 (2015).
  • Blowing Magnetic Skyrmion Bubbles W. Jiang, P. Upadhyaya, W. Zhang, G. Yu, M. B. Jungfleisch, F. Y. Fradin, J. E. Pearson, Y. Tserkovnyak, K. L. Wang, O. Heinonen, S. G. E. te Velthuis, and A. Hoffmann, Science 349, 283 (2015).
  • Reduced spin-Hall effects from magnetic proximity W. Zhang, M. B. Jungfleisch, W. Jiang, Y. Liu, J. E. Pearson, S. G. E. te Velthuis, A. Hoffmann, F. Freimuth, and Y. Mokrousov, Physical Review B 91, 115316 (2015).
  • Spin Hall Effects in Metallic Antiferromagnets W. Zhang, M. B. Jungfleisch, W. Jiang, J. E. Pearson, A. Hoffmann, F. Freimuth, and Y. Mokrousov, Physical Review Letters 113, 196602 (2014).
  • Realization of a spin-wave multiplexer K. Vogt, F. Y. Fradin, J. E. Pearson, S. D. Bader, T. Sebastian, B. Hillebrands, A. Hoffmann, and H. Schultheiss, Nature Communications 5, 3727 (2014).
  • Determination of the Pt spin diffusion length by spin-pumping and spin Hall effect W. Zhang, V. Vlaminck, J. E. Pearson, R. Divan, S. D. Bader, and A. Hoffmann, Applied Physics Letters 103, 242414 (2013).
  • Spin Hall Effects in Metals A. Hoffmann, IEEE Transactions on Magnetics 49, 5172 (2013).
  • Thermoelectric detection of spin waves H. Schultheiss, J.E. Pearson, S.D. Bader and A. Hoffmann, Physical Review Letters 109, 237204 (2012).
  • Spin waves turning a corner K. Vogt, H. Schultheiss, S. Jain, J. E. Pearson, A. Hoffmann, S. D. Bader, and B. Hillebrands, Applied Physics Letters 101, 042410 (2012).
  • Detection and quantification of inverse spin Hall effect from spin pumping in permalloy/normal metal bilayers O. Mosendz, V. Vlaminck, J. E. Pearson, F. Y. Fradin, G. E. W. Bauer, S. D. Bader, and A. Hoffmann, Physical Review B 82, 214403 (2010).
  • Surface spin flip probabilities in mesoscopic Ag wires G. Mihajlović, J. E. Pearson, S. D. Bader, and A. Hoffmann, Physical Review Letters 104, 237202 (2010).
  • Quantifying spin Hall angles from spin pumping: Experiments and theory O. Mosendz, J. E. Pearson, F. Y. Fradin, G. E. W. Bauer, S. D. Bader, and A. Hoffmann, Physical Review Letters 104, 046601 (2010).
  • Negative Nonlocal Resistance in Mesoscopic Gold Hall Bars: Absence of the Giant Spin Hall Effect G. Mihajlović, J. E. Pearson, M. A. Garcia, S. D. Bader, and A. Hoffmann, Physical Review Letters 103, 166601 (2009).
  • Symmetry driven irreversibilities at ferromagnetic-antiferromagnetic interfaces A. Hoffmann, Physical Review Letters 93, 097203 (2004).

Articles in Conference Proceedings

  • Terahertz emission from magnetic thin film and patterned heterostructures S. Lendinez, Y. Li, W. Wu, M. T. Kaffash, Q. Zhang, W. Zhang, J. E. Pearson, R. Divan, R. D. Schaller, A. Hoffmann, H. Wen, and M. B. Jungfleisch, Proceedings of the SPIE 11090, Spintronics XII, 1109013 (2019).
  • Direct Detection of Multiple Backwar Volume Modes in Yttrium Iron Garnet at Micron Scale Wavelengths J. Lim, W. Bang, J. Trossman, A. Kreisel, A M. B. Jungfleisch, Hoffmann, C. C. Tsai, and J. B. Ketterson. Proceedings 26, 48 (2019).
  • Optical Detection of Phase-Resolved Ferromagnetic Resonance in Epitaxial FeCo Thin Films Y. Li, F. Zeng, H. Saglam, J. Sklenar, J. E. Pearson, T. Sebastian, Y. Wu, A. Hoffmann, and W. Zhang, IEEE Transactions on Magnetics 55, 6100605 (2019).
  • Spincaloritronics Measurements: A Round Robin Comparison of the Longitudinal Spin Seebeck Effect A. Sola, V. Basso, M. Kuepferling, M. Pasquale, D. C. né Meier, G. Reiss, T. Kuschel, T. Kikkawa, K.-i. Uchida, E. Saitoh, H. Jin, S. J. Watzman, S. Boona, J. Heremans, M. B. Jungfleisch, W. Zhang, J. E. Pearson, A. Hoffmann, and H. Schumacher, IEEE Transactions on Instrumentation and Measurement 68, 1765 (2019).
  • Study of Surface Character of Micrometer-Scale Dipole-Exchange Spin Waves in an Yttrium Iron Garnet Film J. Lim, W. Bang, J. Trossman, A. Kreisel, M. B. Jungfleisch, A. Hoffmann, C. C. Tsai, and J. B. Ketterson IEEE Transactions on Magnetics 55, 6100504 (2019).
  • Spin pumping and inverse Rashba-Edelstein effect in NiFe/Ag/Bi and NiFe/Ag/Sb W. Zhang, M. B. Jungfleisch, W. Jiang, J. E. Pearson, and A. Hoffmann, Journal of Applied Physics 117, 17C727 (2015).
  • Non-local spin injection in lateral spin valves Y. Ji, A. Hoffmann, J. S. Jiang, J. E. Pearson, and S. D. Bader, Journal of Physics D: Applied Physics 40, 1280 (2007).

Pending Articles

  • Direct Observation of Spin Accumulation in Cu Induced by Spin Pumping J. Ding, W. Zhang, M. B. Jungfleisch, J. E. Pearson, H. Ohldag, V. Novosad, and A. Hoffmann, Physical Review Research, to be published.

Invited Lectures

  • Spin Currents with Antiferromagnets
  • Spin Current Generation, Detection, and Transport with Antiferromagnets
  • Spin currents in metallic antiferromagnets
  • Spin Current Generation, Detection, and Transport with Antiferromagnets
  • Thermal Spin Currents in Antiferromagnets
  • Spin Current Generation, Detection, and Transport with Antiferromagnets
  • Spins in Copper
  • Topological Quasiparticles: Magnetic Skyrmions
  • Spin Current Generation, Detection, and Transport with Antiferromagnets
  • Manipulating Magnetic Skyrmions
  • Manipulating Magnetic Skyrmions
  • Topological Quasiparticles: Magnetic Skyrmions
  • Manipulating Magnetic Skyrmions
  • Topological Quasiparticles: Magnetic Skyrmions
  • Driving Magnetization Dynamics in Insulators Using Spin Hall Effects
  • Spin Hall Effects in Metals
  • Electric Manipulations of Spin Textures
  • Connecting Spinwaves to Charge Currents in Ferromagnetic/Non-magnetic Heterostructures
  • Quantifying Spin Hall Effects in Metals
  • Teaching Electrons New Tricks: Pure Spin Currents
  • Quantifying Spin Hall Effects in Metals
  • Teaching Electrons New Tricks: Pure Spin Currents
  • Pure Spin Currents in Lateral Spin-Valves
  • Shaken Not Stirred: Magnetic Viruses for Biomagnetic Sensing
  • Lateral Spintransport: Teaching Electrons New Tricks

Journal Editorships

  • Associate Editor, Journal of Applied Physics, since 2009

Research Honors

  • Highly Cited Researcher for 2019, Web of Science Group (2019)
  • Distinguished Performance Award, University of Chicago (2017)
  • Fellow, American Vacuum Society (2017)
  • President's International Fellowship, Chinese Academy of Sciences (2016)
  • Outstanding Researcher Award of the AVS Prairie Chapter, American Vacuum Society (2015)
  • Fellow, IEEE (2014)
  • Fellow, American Physical Society (2011)
  • Distinguished Lecturer, IEEE Magnetics Society (2011)
  • Senior Membership, IEEE (2009)

Public Service Honors

  • Outstanding Referee, American Physical Society (2014)

Other Honors

  • Director’s Funded Postdoctoral Fellowship, Los Alamos National Laboratory, Los Alamos, NM (1999)
  • Springorum Medal for Diploma thesis with honors, Rheinisch-Westfälische Technische Hochschule Aachen, Aachen, Germany (1995)

Courses Taught

  • MSE 598 - Magnetic Mat'ls & Applications