Brillouin light scattering and ferromagnetic resonance in sputtered NiFe/Cu/NiFe thin films

Abstract
The spin-wave spectra of Ni 81 Fe 19 (t)/ Cu(25 Å)/Ni 81 Fe 19 (t) with t=200 and 300 Å are investigated by means of Brillouinlight scattering and ferromagnetic resonance. Samples grown on three different substrates, namely, MgO(100), MgO(110), and sapphire(0001), exhibit clear-cut volume and surface modes. Sharp linewidths are signatures of the excellent quality of the samples. Angle-dependent measurements reveal that, while the samples grown on MgO(100) and sapphire(0001) are nearly isotropic, a surprisingly large in-plane uniaxial anisotropy is a characteristic feature of the samples grown on MgO(110). Quantitative agreement between theoretical and experimental results is reported for a realistic set of the samples’ parameters.