Ferromagnetic resonance laboratory

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Obrázek 1: Schematické znázornění metody ŠP-FMR.
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Head: Denys Musiienko, D.Sc.(Tech.)

Previous heads: Ing. Luděk Kraus, CSc, Zdeněk Frait, RNDr., DrSc. (founder)

Research area

We perform microwave ferromagnetic resonance (FMR) measurements to quantify magnetisation dynamics and magnetic anisotropies across a wide range of materials. Our core platforms are a coplanar waveguide (CPW) broadband set-up spanning 1–50 GHz (with optional electrical leads to the sample) and rectangular waveguide resonators at fixed frequencies (X-, Ka- and Q-bands) for high sensitivity. Both platforms are powered by Rohde & Schwarz SMA100B microwave generator and utilise 15” Varian V-3800 magnet for the magnetic field sweep up to 27 kOe. Broadband ferromagnetic resonance (BB-FMR) set-up is schematically drawn in Figure 1. Example of BB-FMR measurements of 20 nm thick Ni-Mn-Ga film deposited on a substrate demonstrate the sensitivity of the method in Figure 2.

Figure 1: Schematic representation of the BB-FMR method.
Description
Figure 1: Schematic representation of the BB-FMR method.
Figure 2: Example of BB-FMR measurements of 20 nm thick magnetic shape memory film.
Description
Figure 2: Example of BB-FMR measurements of 20 nm thick magnetic shape memory film.

Instrumental capabilities:

  • Broadband FMR: 1–50 GHz (CPW)
  • Fixed-frequency waveguide resonators (X-, Ka- and Q-bands)
  • Angular scans (in-plane / out-of-plane; set-up dependent)
  • Temperature-dependent studies
  • Optional electrical contacts to sample

What can be measured:

  • Effective magnetisation, g-factor, anisotropy fields (magnetocrystalline, uniaxial, surface/interface).
  • Linewidth analysis separation of intrinsic damping and extrinsic broadening (inhomogeneity, scattering-type contributions).
  • Mode structure (multiple peaks, standing spin-wave features) exchange/spin-wave information, confinement, and electrodynamic effects.
  • Temperature / phase tracking anisotropy and magnetisation changes across transformations.