Polarization of Pd atoms and interlayer coupling in Fe-Si/Pd multilayers

In this paper two series of Fe-Si/Pd multilayers are made by rf sputtering and studied by vibrating sample magnetometry and electronic paramagnetic resonance spectroscopy. For Fe-Si/Pd (5.4 nm) multilayers with increasing Fe-Si layer thickness, the saturation magnetization M_s decreases. This is an evidence of the spin-polarization of Pd atoms. An interlayer coupling is confirmed to exist by spin wave modes in Fe-Si (1.5 nm)/Pd multilayers with Pd layer thickness d_pd ≤ 7.2 nm, except for d_pd = 1.8 nm. For d_pd = 1.8 nm no interlayer coupling occurs, and both the saturation magnetization M_s and the effective magnetization 4πM_eff have a minimum. The resonance linewidth ΔH changes correspondingly with the effective magnetization as a function of d_pd and has a maximum at d_pd of 1.8 nm.