Measurement of the dynamical dipolar coupling in a pair of magnetic nano-disks using a Ferromagnetic Resonance Force Microscope

Benjamin Pigeau (1) , Christian Hahn (1) , G. de Loubens (1) , V. V. Naletov (1) , Olivier Klein (1) , Kaname Mitsuzuka (2) , M. Hehn (2) , S. Andrieu (2) , Daniel Lacour (2) , F. Montaigne (2)

1 SPEC - UMR3680 - Service de physique de l'état condensé
2 IJL - Institut Jean Lamour

We perform an extensive experimental spectroscopic study of the collective spin-wave dynamics occurring in a pair of magnetic nano-disks coupled by the magneto-dipolar interaction. For this, we take advantage of the stray field gradient produced by the magnetic tip of a ferromagnetic resonance force microscope (f-MRFM) to continuously tune and detune the relative resonance frequencies between two adjacent nano-objects. This reveals the anti-crossing and hybridization of the spin-wave modes in the pair of disks. At the exact tuning, the measured frequency splitting between the binding and anti-binding modes precisely corresponds to the strength of the dynamical dipolar coupling $\Omega$. This accurate f-MRFM determination of $\Omega$ is measured as a function of the separation between the nano-disks. It agrees quantitatively with calculations of the expected dynamical magneto-dipolar interaction in our sample.

Domaines: Science des matériaux [cond-mat.mtrl-sci]

Benjamin Pigeau, Christian Hahn, G. de Loubens, V. V. Naletov, Olivier Klein, et al.. Measurement of the dynamical dipolar coupling in a pair of magnetic nano-disks using a Ferromagnetic Resonance Force Microscope. Physical Review Letters, 2012, 109, pp.247602. ⟨10.1103/PhysRevLett.109.247602⟩. ⟨hal-00719565⟩