Additional measurements were carried out using the wide microstrip transducer and a hollow waveguide. As follows from Ref. [22], the microwave field of a 1.5 mm-wide microstrip transducer should be homogeneous above the transducer at distances less than 1.5 mm from the surface. This allows taking measurements with a sample placed on the transducer with its Si-substrate (0.5 mm thick) facing the transducer. A representative result of such a measurement with a Si/Py/Co sample is shown in Fig. 7. With the film facing the transducer, the response is Type A. The response changes to Type B when the sample is placed with the substrate facing the transducer. This is consistent with the above measurements on Si/Co/Py structures and the theoretical predictions given in Ref. [14]. Following Appendix B, Case A in Ref. [14] the same effect of swapping response types should be seen for propagating plane electromagnetic waves incident normally onto the film surface. We tested this using a hollow metallic waveguide of rectangular cross-section to form conditions for the normal incidence. The films are placed in the cross sectional plane of the waveguide. The measurements are made in reflection, so that the parameter S11 [2] is obtained. The samples fill about one half of the the waveguide cross-section. For this reason one has to expect a microwave field incident on the rear sample surface that includes contributions from diffraction around edges of the sample. The presence of this diffracted field is confirmed by VNA measurements. When a sample is inserted into the waveguide, the transmission characteristic S 21( f ) acquires a non-monotonic dependence on frequency f because of partial standing wave resonances formed in the waveguide. S 21 varies from -6db to -12dB depending on f . Our field resolved measurements are carried out in a local minimum of S 21( f ) in order to reduce effects of the diffracted microwave field at the rear sample surface. Representative data are displayed in Fig. 8. We find the same tendency as in the microstrip experiments: responses of Type A are obtained when the Co layer of any structure faces the incident flux, and responses of Type B are obtained when the Py layer faces the incident flux. Here we give basic elements of the theory in a broader context of previous studies for eddy-current effects for conducting films. Details of the theory can be found in Ref. [14]. 6. Discussion 12