Spin wave excitations in exchange-coupled [Co/Pd]-NiFe films with tunable tilting of the magnetization

Brillouin light scatteringwas applied tomeasure the evolution of spinwaves in exchange-coupled [Co/Pd]-NiFefilms with out-of-plane/in-plane magnetic anisotropy. Tunable tilting of the magnetization has important effectson the spin wave frequency gap: a substantial increase is observed with decreasing the soft NiFe thickness, whileseemingly insignificant tilting angles cause a strong reduction with respect to a film with only the hard [Co/Pd]component. The spin wave frequency is reproduced also in samples, with increased thickness of the upper Pdlayer, where a sudden modification in the tilting at the hard/soft interface is caused by the weakening of interlayerexchange.