Frequency multiplication by collective nanoscale spin-wave dynamics

Lecture & Talk

  • Datum: 23.05.2022
  • Uhrzeit: 14:00 - 15:45
  • Vortragender: Chris Körner & Prof. Georg Woltersdorf
  • Ort: MPI Halle
  • Raum: Lecture Hall, B.1.11
  • Gastgeber: IMPRS-STNS
  • Kontakt:
Frequency multiplication by collective nanoscale spin-wave dynamics
In the scientific field of magnetism, attention is moving towards ever more complicated magnetic textures. Simple ferromagnetic materials, however, seem to have nothing interesting to offer anymore. Or, do they?

In a recently published study[1] we investigated the dynamics of a simple ferromagnet due to radiofrequency driving. Similar experiments are frequently done for many years. Their results are well understood. Very surprisingly, in our study, we found an entirely unexpected new effect, which has not been described previously. When driving the magnetization with frequencies far below their ferromagnetic resonance, i.e. in the MHz range, it responds with a number of multiples of the driving frequency. These frequencies span a comb ranging up to several GHz. As a result, a simple magnetic material can convert MHz input into multi GHz output frequencies without the need for complicated device structures or materials.

Prof. Georg Woltersdorf will start with a lecture-like broad introduction to the field of magnetization dynamics. This will cover collective dynamic magnetic excitations, known as spin-waves, the discussion of various means to detect magnetic excitations, and finally the details of nonlinear phenomena as well as switching processes.

Chris Körner will present their recent Science publication and explore the mechanism which is responsible for the comb generation in detail.

[1] C. Koerner, R. Dreyer, M. Wagener, N. Liebing, H. G. Bauer and G. Woltersdorf, Frequency multiplication by collective nanoscale spin-wave dynamics. Science 375, 1165–1169 (2022)

The event will take place according to 3G rules. In the Lecture Hall, the participants have to wear a medical mask.

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