Coercivity tuning in Co/Pd multilayer based bit patterned media

In order to adjust the reversal field of high anisotropy [Co(2.8 Å)/Pd(9 Å)]8 bit patterned media (BPM), one may increase the individual Co thickness to change the overall anisotropy or alternatively combine the high anisotropy multilayer with a lower anisotropy material, thus creating a heterogeneous laminated system. In the current study, we find that [Co/Pd]8−N[Co/Ni]N hard-soft laminated BPM allows tuning the coercivity while maintaining a narrow normalized switching field distribution (σSFD/HC), whereas homogeneous structures with increased individual Co thickness show a more pronounced increase in σSFD/HC. Possible reasons for the different behavior, such as changes in strain and texture, are discussed.