Magnonic Band Structure of Domain Wall Magnonic Crystals

Magnonic crystals (MCs) are prototype magnetic metamaterials designed for the control of spin wave propagation. Conventional MCs are composed of single domain elements. If magnetization textures, such as domain walls (DWs), vortices, and skyrmions, are included in the building blocks of MCs, additional degrees of freedom over the control of the magnonic band structure can be achieved. We theoretically investigate the influence of DWs on the spin wave propagation and the corresponding magnonic band structure. It is found that the rotation of magnetization inside a DW introduces a geometric vector potential for the spin wave excitation. The corresponding Berry phase has quantized value 4n
_w
π, where nw is the winding number of the DW. Due to the topological vector potential, the magnonic band structure of MCs with DWs as comprising elements differs significantly from an identical MC composed of only magnetic domains. This difference can be utilized to realize dynamic reconfiguration of magnonic band structure by a sole nucleation or annihilation of DWs in MCs.