k -value). One can relate this to disappereance of the contribution of the screening field h$_{Oek}$ to the total dynamic magnetic field of the film. 

In summary, for the broad transducers considered in the present paper, the homogeneity of the microwave field in the film plane, together with film thicknesses small compared to the microwave skin depth, form conditions for observation of pronounced eddy current effects. We present below experimental evidence for eddy current effects in what follows, and show that these effects provide quantitative descriptions for observed intensities. 

## 3. Experiment 

Measurements are made with the sample placed on a section of the microwave transducer carrying an AC microwave current as illustrated in Fig. 1. The magnetization is aligned along the axis of the coplanar stripline by an applied static DC bias field. Current through the transducer generates an oscillating magnetic field in the sample perpendicular to the equilibrium magnetization. Resonant absorption is detected by measuring transmitted in- tensities through the transducer. Transmission measurements were made with very little attenuation from the cables or waveguide. The strength of the bias field is swept from 0 to 0.6 Tesla, at a fixed frequency of the ac current. This is repeated across the available range of frequencies (100 MHz to 20 GHz). In this way frequencies are chosen which avoid any waveguide resonances or sample reflections. The magnetic contribution of the signal is extracted by measuring a reference signal at a field large enough (1 T) to suppress any of the resonances. This range allows an optimal compromise between choosing thicker films in order to detect low frequency SSWM modes and measuring surface effects that fall off according to 1 /t . 

The samples were deposited by magnetron sputtering at an argon working pressure of 2.5 mTorr. Two series of samples were grown, each containing bilayer and single layer films. Details of each series are listed in Table 1. All samples in a given series were grown during the same vacuum cycle in order to ensure consistency. The base pressure prior to the deposition was of the order of 1 × 10 − 8 Torr. The film structures Ta(5 nm)/Py( t$_{Py}$ nm)/Co( t$_{Co}$ nm)/Ta(2.5 nm (Series 1) or 5 nm (Series 2)) were deposited onto silicon (100) substrates in an in-plane forming field of magnitude 200 Oe at ambient temperature. De- position rates were determined by measuring the thickness of calibration films by low angle 

