how to treat lattice mismatch of a GMR junction

[baizq]

Dear colleagues,

How to treat the GMR junctions, of which the electrode and space layer have a lattice mismatch?

For example, in Co/Cu/Co spin valve, the lattice constant of fcc Cu is 3.615A, whereas it is 3.5447A for fcc Co. There is around 2% lattice mismatch. How should we deal with this? It is correct to compress the lattice constant of Cu spacer to the same value as Co (force Cu lattice constanct to be 3.5447A)? Will this method lead to large error?
Or should we conduct a relaxation first to determine all geometry factors of the system, such as the lattice constancts of both spacer and eletrode, the distance between the last screening layer and the first space layer, and so on....

Thanks
baizq

[Anders Blom]

There is no way around introducing some amount of strain, if the electrode and space do not have the same lattice constant in X/Y. However, one should also consider whether this might actually be what is occurring in the real sample. After all, if the spacer is grown on top of the electrode, it might form a lattice matching (strained) structure as long as the spacer layer is thin.