  We have used time-resolved scanning Kerr microscopy (TRSKM) and micromagnetic
simulations to demonstrate that, when driven by spatially uniform microwave
field, the edges of patterned magnetic samples represent both efficient and
highly tunable sources of propagating spin waves. The excitation is due to the
local enhancement of the resonance frequency induced by the non-uniform dynamic
demagnetizing field generated by precessing magnetization aligned with the
edges. Our findings represent a crucial step forward in the design of nanoscale
spin-wave sources for magnonic architectures, and are also highly relevant to
the understanding and interpretation of magnetization dynamics driven by
spatially-uniform magnetic fields in patterned magnetic samples.
