Laser Spintronics Group

About

In our group, we investigate physical mechanisms governing the charge and spin dynamics in thin films, metallic thin film stacks and emerging materials. Our pump-probe experimental technique allows tracking of the optically triggered ultrafast phenomena with femtosecond time resolution and element selectivity. The acquired knowledge is essential for the development of future spin-based electronics and quantum computing devices.

Research Topics

  • Femtosecond Spectroscopy and Spin Dynamics
  • Spintronic THz Emitters
  • All Optical Switching
  • High Harmonic Generation

Contact

Dr. Roman Adam

PGI-6

Building 04.8 / Room R 258

+49 2461/61-5196

E-Mail

Members

FURTHER GROUP MEMBERS

Sarah Heidtfeld


Contact:
Dudenstraße 13, 4413
Building: 04.8/ Raum: 235
Telefone: 017630754372
E-Mail

Fangzhou Wang


Contact:
Building: 04.8/ Raum: 235
Telefone: +49 2461/61-5196
E-Mail

Derang Cao


Contact:
Building: 04.8/ Raum: 235
Telefone: +49 2461/61-5196
E-Mail

Research Topics

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Femtosecond Spectroscopy and Spin Dynamics

In thin ferromagnetic films, electron spin can be controlled on femtosecond time scales using laser-generated light pulses. Harnessing this technology can lead to dramatic advancements in ultrafast electronics and quantum computing. We explore non-equilibrium spin dynamics in ferromagnetic thin films and multilayers employing femtosecond laser spectroscopy in visible and XUV spectral ranges.

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Spintronic THz Emitters

Terahertz (THz) radiation refers to the part of the electromagnetic spectrum that typically covers frequencies between 300 GHz and 30 THz. We study the performance of spintronic THz emitters, in order to understand the underlying physical mechanisms governing THz emission, as well as the application potential of such emitters in scientific experiments.

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All Optical Switching (AOS)

Optically driven magnetization reversal in ferro- and ferrimagnetic thin films, by employing short laser pulses, is one the most fascinating topics of the current research. In these experiments we demonstrate that magnetization can be switched by means of optical pulses in the absence of external magnetic field. We investigate magnetization reversal in GdFeCo ferrimagnetic alloys and ferromagnetic [Co/Pt]N superlattices as a function of material composition, thickness, number of layers, as well as laser beam properties.

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High Harmonic Generation (HHG)

Focusing an intense laser pulse into a collection of gas atoms results in the generation of high-order harmonics of the fundamental light, which extend into the extreme ultraviolet (XUV) spectral range (photon energies 10-120 eV). We use resonant XUV light absorption for time-resolved XUV spectroscopy of complex magnetic alloys and multilayers.

Publications

X. Chen, R. Adam, D. E. Bürgler, F. Wang, Z. Lu, L. Pan, S. Heidtfeld, C. Greb, M. Liu, Q. Liu, J. Wang, C. M. Schneider, and D. Cao, Ultrafast demagnetization in ferromagnetic materials: Origins and progress, Physics Reports 1102, 1 (2025)
https://doi.org/10.1016/j.physrep.2024.10.008

R. Adam, D. Cao, D. E. Bürgler, S. Heidtfeld, F. Wang, C. Greb, J. Cheng, D. Chakraborty, I. Komissarov, M. Büscher, M. Mikulics, H. Hardtdegen, R. Sobolewski, and C. M. Schneider, THz generation by exchange-coupled spintronic emitters, npj Spintronics 2, 58 (2024)
https://doi.org/10.1038/s44306-024-00061-0

G. Chen, D. Chakraborty, J. Cheng, M. Mikulics, I. Komissarov, R. Adam, D. E. Bürgler,
C. M. Schneider, H. Hardtdegen, and R. Sobolewski, Transient THz emission and effective mass determination in highly resistive GaAs crystals excited by femtosecond optical pulses, Crystals 12 (2022)
https://doi.org/10.3390/cryst12111635

S. Heidtfeld, R. Adam, T. Kubota, K. Takanashi, D. Cao, C. Schmitz-Antoniak, D. E. Bürgler, F. Wang, C. Greb, G. Chen, I. Komissarov, H. Hardtdegen, M. Mikulics, R. Sobolewski, S. Suga, and C. M. Schneider, Generation of terahertz transients from Co2Fe0.4Mn0.6Si Heusler-alloy/normal-metal nanobilayers excited by femtosecond optical pulses, Phys. Rev. Research 3, 043025 (2021)
https://doi.org/10.1103/PhysRevResearch.3.043025

U. Parlak, R. Adam, D. E. Bürgler, S. Gang, and C. M. Schneider, Optically induced magnetization reversal in [Co/Pt]N multilayers: Role of domain wall dynamics, Phys. Rev. B 98, 214443 (2018)
https://doi.org/10.1103/PhysRevB.98.214443

S. Gang, R. Adam, M. Plötzing, M. von Witzleben, C. Weier, U. Parlak, D. E. Bürgler, C. M. Schneider, J. Rusz, P. Maldonado, and P. M. Oppeneer, Element-selective investigation of femtosecond spin dynamics in nipd magnetic alloys using extreme ultraviolet radiation, Phys. Rev. B 97, 064412 (2018)
https://doi.org/10.1103/PhysRevB.97.064412

S. Eich, M. Plötzing, M. Rollinger, S. Emmerich, R. Adam, C. Chen, H. C. Kapteyn, M. M. Murnane, L. Plucinski, D. Steil, B. Stadtmüller, M. Cinchetti, M. Aeschlimann, C. M. Schneider and S. Mathias, Band structure evolution during the ultrafast ferromagnetic-paramagnetic phase transition in Cobalt, Sci. Adv. 3, e1602094 (2017)
https://doi.org/10.1126/sciadv.1602094

D. Rudolf, C. La-O-Vorakiat, M. Battiato, R. Adam, J. M. Shaw, E. Turgut, P. Maldonado, S. Mathias, P. Grychtol, H. T. Nembach, T. J. Silva, M. Aeschlimann, H. C. Kapteyn, M. M. Murnane, C. M. Schneider, and P. M. Oppeneer, Ultrafast magnetization enhancement in metallic multilayers driven by superdiffusive spin current, Nature Communications 3, 1037 (2012)
https://doi.org/10.1038/ncomms2029

Last Modified: 26.02.2025
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