PHONON ASSISTED MAGNON TRANSMISSION THROUGH NICKEL AT 24-GHZ

According to conventional theories of microwave transmission through ferromagnetic metals the transmission of 24 GHz radiation through nickel slabs 5-10 μm thick should be unobservable. Nevertheless, experiments at room temperature have revealed a peak in the transmission of 24 GHz microwaves at FMR using nickel single crystals and annealed polycrystalline foils ca. 8 μm thick. It is proposed that this anomalous energy transport across the specimens at FMR is due to the phonon mode which is generated by magneto-elastic coupling to the resonantly precessing magnetization. The calculations indicate that exchange plays a significant role in determining the intensity and the lineshape of the transmitted signal at FMR.