Effect of roughness and continuity of Co layers to magnetic properties of Co/Pd multilayers

High Ar gas pressure condition for deposition of Pd interlayers and underlayers in [Co/Pd]N/Pd multilayers caused the increase of surface roughness. Such an increase of surface roughness is strongly related to the decrease of loop gradient factor of M-H loop α(=4π(dM/dH)atH=Hc) as well as large increase of coercivity Hc. In order to confirm the effect of continuity of grains in Co/Pd multilayer, we tried to deposit [Co/Pd]20 multilayer in which the Co and Pd layers were deposited at different Ar gas pressure for each layer. When Pd layer was deposited at low PAr, the multilayer did not reveal high Hc. The deposition of Pd layers at high PAr enhances average surface roughness Ra of the multilayers. High Hc and low α seem to be attributed to the discontinuity of the Co layers which causes the surface roughness. PAr condition for the deposition of Co affected strongly to α, which is strongly correlated to the continuity of the layer in the lateral direction.