Impedance and surface impedance of ferromagnetic multilayers: the role of exchange interaction

A theory of impedance and surface impedance in conductive ferromagnetic films and layered magnetic/conductor structures is presented. The theory is based on solving Maxwell's equations for the magnetic and electric fields and the Landau-Lifshitz equations for the magnetization. The exchange interaction in the magnetic films as well as pinning at surfaces are taken into account. The analytical results obtained demonstrate the importance of the exchange, pinning and also the type of excitation the magnetic systems are subject to in describing their properties at ultrahigh frequencies.