Arbeitsgruppe Prof. Hillebrands

Welcome to the magnetism group!

We are dedicated to cutting-edge research in the field of magnonics and related areas combined with excellent teaching.

Magnonics is a subfield of spintronics, which addresses the utilization of the spin degree of freedom for applications in information and communication technologies. We study „magnetic waves“, which are spin waves and their quanta called magnons, and we address new fundamental phenomena and their potential for applications. A particular focus is on macroscopic quantum phenomena such as supercurrents and their utilization, as well as on the development of magnonic devices for the information technology.

Our research is embedded in the Collaborative Research Center 173 „Spin+X“ funded by the Deutsche Forschungsgemeinschaft, as well as by several national, European and international projects. We offer opportunities for qualification in the frames of student assistantships, bachelor, master diploma and PhD projects in an international environment.



Our article "Local temperature control of magnon frequency and direction of supercurrents in a magnon Bose–Einstein condensate" has been selected as a "Featured Article" and is displayed on the cover of Applied Physics Letters

The creation of temperature variations in magnetization, and hence in the frequencies of the magnon spectrum in laser-heated regions of magnetic films, is an important method for studying Bose–Einstein condensation of magnons, magnon supercurrents, Bogoliubov waves, and similar phenomena. In our study, we demonstrate analytically, numerically, and experimentally that, in addition to the magnetization variations, it is necessary to consider the connected variations of the demagnetizing field. In the case of a heat-induced local minimum of the saturation magnetization, the combination of these two effects results in a local increase in the minimum frequency value of the magnon dispersion at which the Bose–Einstein condensate emerges. As a result, a magnon supercurrent directed away from the hot region is formed.


Our article "Persistent magnetic coherence in magnets" has been published in Nature Materials

When excited, the magnetization in a magnet precesses around the field on a timescale governed by viscous magnetization damping, after which any information carried by the initial actuation seems to be lost. This damping appears to be a fundamental bottleneck for the use of magnets in information processing. However, here we demonstrate the recall of the magnetization-precession phase after times that exceed the damping timescale by two orders of magnitude using dedicated two-colour microwave pump–probe experiments for an YIG microstructured film. Time-resolved magnetization state tomography confirms the persistent magnetic coherence by revealing a double-exponential decay of magnetization correlation. We attribute persistent magnetic coherence to a feedback effect, that is, coherent coupling of the uniform precession with long-lived excitations at the minima of the spin-wave dispersion relation. Our finding liberates magnetic systems from the strong damping in nanostructures that has limited their use in coherent information storage and processing.
See Publication


Our papers "Bose-Einstein condensation in systems with flux equilibrium" and "Towards an experimental proof of the magnonic Aharonov-Casher effect" have been selected for Editors’s Suggestions in Physical Review B

Quasiparticles, created in dissipative nonlinear wave systems by external excitation, can form a Bose-Einstein condensate. In this article, we describe the physical phenomena and conditions leading to condensation in various regimes of external excitation from weak and stationary to ultrastrong pumping. We have developed a stationary nonlinear theory of kinetic instability for the latter, supported by the experimental data for magnons, parametrically pumped in roomtemperature films of yttrium iron garnet.

Phys. Rev. B 109, 014301 (2024)

The Aharonov-Casher effect is the accumulation of the wave function phase when a particle with magnetic moment passes through an electric field. This phenomenon is observed for real particles and predicted for quasiparticles such as magnons. In this letter, we investigate the impact of a strong electric field on the phase of dipolar spin waves exited in a ferromagnetic yttrium iron garnet (YIG) film and report the experimental results in favor of the magnonic Aharonov-Casher effect.

Phys. Rev. B 108, L220404 (2023)

Recent Publications

Nonlinear erasing of propagating spin-wave pulses in thin-film Ga:YIG
D. Breitbach, M. Bechberger, B. Heinz, A. Hamadeh, J. Maskill, K. Levchenko, B. Lägel, C. Dubs, Q. Wang, R. Verba, and P. Pirro
Appl. Phys. Lett. 124, 092405 (2024)

Local temperature control of magnon frequency and direction of supercurrents in a magnon Bose–Einstein condensate
M. R. Schweizer, F. Kühn, V. S. L’vov, A. Pomyalov, G. von Freymann, B. Hillebrands, and A. A. Serga
Appl. Phys. Lett. 124, 092402 (2024).

Persistent magnetic coherence in magnets
T. Makiuchi, T. Hioki, H. Shimizu, K. Hoshi, M. Elyasi, K. Yamamoto, N. Yokoi, A. A. Serga, B. Hillebrands, G. E. W. Bauer, and E. Saitoh
Nature Materials (2024)

More Publications



Zum Seitenanfang