Band structures of two-dimensional magnonic crystals with different shapes and arrangements of scatterers

The spin-wave band structures of two-dimensional magnonic crystals with different shapes and arrangements of scatterers are investigated numerically. It is shown that the magnonic band gap of spin waves in magnonic crystals can be optimized by changing the shape or the arrangement of scatterers in background materials. The largest absolute gap can be achieved when the scatterer has the same symmetry as that of the coordination polygon of lattice point, such as the case of square rods in square lattices. For a given shape of scatterer, the gap width is the largest when the lattice has the largest coordination number if the scatterer does not reduce the symmetry.