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 fFMR 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.