Magnetoimpedance of NiFe/Ag multilayers in the 100kHz–1.8GHz range

Abstract Magnetoimpedance curves at frequencies up to 1.8 GHz for (Ni 81 Fe 19 /Ag) n multilayers with n =15, 50 and 100, and thickness ratio t Py / t Ag : 100 7 , 100 25 , 100 100 , 200 14 , 200 50 and 200 200 A are presented. Evidences of FMR are observed in most samples studied. Samples with 15, 50 and 100 bilayers exhibited a maximum MI ratio of about 100%, 175% and 250%, respectively. For samples with t Py =4t Ag , peculiar impedance spectra with 4 peaks were observed.