The electronic structure of the metals of the first transition period

Abstract

Three distinct lines of experimental work now point towards a new conception of the electronic structure of the transition metals. Recent x-ray work has shown that in Fe and Cr the valence electrons are not as well localized near the atoms as had been supposed, while in Co, Ni and Cu the compact 3d-shell is nearly complete. Saturation magnetic moments of Ni rich alloys show that Ti and V act as though they had respectively four and five electrons to contribute to the conduction band of Ni. Neutron diffraction evidence shows that pure Ti and V have no magnetic moments, ordered or disordered, and that in Ni-Cr alloys the Cr atom carries a moment not much different from Ni, though each added atom removes nearly 5 μB from the saturation moment. We therefore suggest that elements of atomic number less than Fe have few 3d electrons and many conduction electrons, while for those above iron this is reversed. It appears as though this conclusion can be maintained almost independently of crystal structure or composition of alloy. On this basis the variation of saturation magnetic moment of all the binary ferromagnetic alloys can be explained.