I am comparing potential requirement for Ni and Fe. For Ni EAM potential (only central forces components) are sufficient as they can give fairly good results for physical properties. But for Fe, EAM potentials are not sufficient. They need angular dependent force component also to give results for physical properties which are in fairly good agreement with experimental results.

Why it is so?

Both are d-orbitals elements.

Is it something to relate with magnetism or how?