Abstract:
We report on a comprehensive study of the interlayer exchange coupling in Co-Feð5 nmÞ=RuðtÞ=
Co-Feð8 nmÞ trilayers ðt ¼ 0.8;…; 2.8 nmÞ using broadband ferromagnetic resonance. A systematic
frequency dependence of the field separation between the acoustic and optic modes is found, which
is caused by different effective magnetizations of the two ferromagnetic layers. Hence, it is shown
that the broadband measurements are vital for reducing the systematic error margins in the determination
of interlayer exchange coupling using ferromagnetic resonance. We also investigate the temperature
dependence of the interlayer exchange coupling and compare our results with existing theories.
It is shown that models which take into account the temperature dependence due to thermal excitations
of spin waves within the ferromagnetic layers have a considerably better agreement with the experiment
than models solely based on spacer and interface contributions to the temperature dependence.
