Enhancement of magnetic surface anisotropy of Pd/Co/Pd trilayers by the addition of Sm

We have studied the effect of Sm on the magnetic surface anisotropy (MSA) of Pd/Co100−xSmx/Pd (111) trilayers, where Sm content x was varied from 0 to 11. All samples show perpendicular anisotropy due to the strong MSA at the interfaces. The MSA significantly increases with x and attains a maximum value of 0.60 erg/cm2 at x≃8.3, which is 36% larger than that of pure Co (x=0). The volume term of the magnetic anisotropy shows a similar behavior as the MSA. The appreciable increase in MSA is considered to be due to the enhancement of orbital moment of Co by the addition of Sm.