The high-frequency soft magnetic properties of FeCoSi/MnIr/FeCoSi trilayers

The dynamic properties of as-deposited FeCoSi/MnIr/FeCoSi trilayers, prepared by RF magnetron sputtering method, have been investigated in the frequency range from 100 MHz to 9 GHz. The effective anisotropy fields of the top and bottom CoFeSi and Gilbert constant ( α) are analyzed using the Landau–Lifshitz–Gilbert equation. The experimental result implies that the f FMR can be easily tuned up to 8.2 GHz by controlling the CoFeSi thickness and unidirectional anisotropy. The extracted α decreases as the increasing of exchange bias field, which behavior can be explained as the suppressing of the anisotropy field distribution by exchange bias. Therefore, the exchange biased CoFeSi/MnIr/CoFeSi trilayers with the high ferromagnetic resonance frequency and low loss properties are promising for the high-frequency application.