Dynamics of coupled vortices in a pair of ferromagnetic disks

We here experimentally demonstrate that coupled gyration modes can be resonantly excited primarily by the ac current in a pair of ferromagnetic disks with varied separating distance. The sole gyrotropic mode clearly splits into a higher and a lower frequency modes for different configurations of polarities via dipolar interaction. These experimental results indicate that the magnetostatically coupled pair of vortices behaves similar to a diatomic molecule with bonding and anti-bonding states. These findings lead to the possible extension of designing the magnonic band structure in a chain or an array of vortices.