Quantitative analysis of the giant magnetoresistance effect at microwave frequencies

The high-frequency analog of giant magnetoresistance (GMR) in the microwave reflection and transmission coefficients of spin valves was measured and quantified. The relative change in transmission is nearly a factor of 2 larger than the electrical transport GMR effect. The change in reflection is of opposite sign and an order of magnitude smaller. A calculation of the reflection and transmission coefficients, considering the interfaces and the decay of the fields within the layers, provides a quantitative relationship to the transport GMR with no free parameters.