What do you want to improve? Do you want to have a larger exchnage bias field? In this case you can try to decrease a thickness of a ferromagnet (even beyond the limit for continuous layer formation, see paper attached). Or do you mean something else?
Cheers!
Article The influence of superparamagnetism on exchange anisotropy a...
Yes, we want to increase the exchange bias field. Thanks for your suggestions.
We have tried to change the thickness of the ferromagnetic layer, but our experiments of spin valve fabrication were not well repeated. We are still investigating this issue.