  We investigate the transfer and control of nonreciprocity through magnons
themselves in permalloy thin films deposited on surface oxide silicon
substrate. Evidences of nonreciprocal emergence of hybridized dipole exchange
magnons (spin waves) at two permalloy surfaces are provided by studying magnon
transmission and asymmetry, via Brillouin light scattering measurements. The
dipole dominated spin wave and exchange dominated spin wave are found to be
localized near the top and bottom surfaces, respectively, and traveling along
opposite directions. The nonreciprocity and the localization are intertwined
and ca n be tuned by an in plane magnetic field. The effects are well explained
by the magnetostatic theory and can be quantitatively reproduced by the
micromagnetic simulations. Our findings provide a simple and flexible approach
to nonreciprocal all magnon logi c devices with highly compatible with silicon
based integrated circuit technology.
