Spin dynamics

Spin dynamics is a second important research line in the Goennenwein group. We measure the ferromagnetic resonance (FMR) response – or more generally the high frequency susceptibility – of thin magnetic films not only at a fixed frequency as a function of the magnetic field strength, but also over a broadband frequency range up to 50GHz. With these experiments, important magnetic parameters such as the g-factor, the saturation magnetization or the magnetic anisotropy can be directly determined. FMR measurements also allow accessing the magnetization damping viz. the lifetime of magnetic excitations. In this context, the so-called spin pumping effect often plays an important role. In spin pumping, a pure spin current is generated from resonantly driven magnetization dynamics. This yields a versatile and well-controlled spin current source. On a different note, broadband FMR experiments are ideally suited to study the coupling of magnetic resonance modes to one another, to the lattice, or to microwave (cavity) modes. This makes it possible to access and investigate different coupling regimes, the coupling strengths, etc.

Czeschka et al., Physical Review Letters 107, 046601 (2011).

Klingler et al., Physical Review Letters 120, 127201 (2018).