Control of Gilbert damping using magnetic metamaterials

We studied, from a theoretical standpoint, the Landau-Lifshitz-Gilbert equation of magnetic metamaterials consisting of magnetic nanoparticles. The dynamics of the metamaterials magnetization was numerically investigated in order to elucidate the mechanism of Gilbert damping. Our results revealed that the interacting dipole field synchronized to the magnetization precession causes the variation in the effective Gilbert damping factor. Nevertheless, we found that a metamaterial with a specific structure has almost the identical effective Gilbert damping factor, although the interacting dipole field increases. This work demonstrates that the effective Gilbert damping factor can be analytically predicted and designed using the structure factors in magnetic metamaterials, opening an avenue to a new relationship between metamaterials and spintronics.