lines: fits for the single-layer film. Blue solid lines: fits for the bi-layer film. f: fundamental mode. 1-3: Standing spin wave modes with respective numbers. Fig. 6. Broadband FMR absorption for bi-layers. Microstrip transducer is 1.5 mm in width. Left-hand panels (a-d): driving frequency is 7.5 GHz. Right-hand panels (e-h): 18 GHz. (a) and (e): Single-layer Permalloy films (Si/Ta/Py/Ta, given here for comparison); solid line: 80 nm thick; dashed line: 40 nm thick; (b-d) and (f-h) are bi-layer responses. Red solid lines are for Si/Ta/Py/Co/Ta and dashed blue lines are for Si/Ta/Co/Py/Ta structures. In all figures Cobalt layer is 10nm thick. (b) and (f): Permalloy thickness is 40 nm; (c) and (g): 60 nm; (d) and (h): 80 nm. Inset to panel (d): cavity FMR data for the respective Si/Py/Co structure (80nm of Py, 10 nm of Co.) The cavity data were taken at 9.47 GHz. Fig. 7. Microwave broadband FMR absorption for the bi-layer from Fig. 5. The 1.5mm- wide microstrip transducer is used. Solid line: film faces the microstrip. Dashed line: film substrate faces the microstrip. Fig. 8. Hollow waveguide data. Frequency is 9.5 GHz. (a): response of Si/Ta/Py[80nm]/Co[10 nm]/Ta structure. (b): response of Si/Ta/Co[10 nm]/Py[80 nm]/Ta structure. Red solid line: Film facing the incident flux. Blue dashed line: substrate facing the incident flux. All measurements were done in reflection (S11 parameter was measured). Fig. 9. (Color online) Calculated profiles of the dynamic magnetization and of the total microwave magnetic field for the bi-layer Py[74nm]/Co[10nm]. (a) and (c) in-plane component of dynamic magnetization m$_{x}$ at 7.5 GHz. (b) and (d): total microwave magnetic field. Left panels: Permalloy layer faces the transducer. Right panels: cobalt layer faces the transducer. Blue lines: phase for the first standing-spin wave mode of the stack (right axes). 24