Vortex mode splitting due to dipolar interactions in disks

Dynamics of Coupled Vortices in a Pair of Ferromagnetic Disks.
Satoshi Sugimoto, Yasuhiro Fukuma, Shinya Kasai, Takashi Kimura, Anjan Barman, and YoshiChika Otani
Phys. Rev. Lett. 106, 197203 (2011)

(a) Experimental setup. (b) Frequency dependence of the normalized dc voltage Vdc=Iac measured for an isolated disk (green triangles) and for the paired disks with different polarities; black squares for p1p2= 1, and red circles for p1p2=-1.