Titanium-induced changes in the electronic structure of iron

Mossbauer effect was used to study changes in the electronic structure of iron caused by substitutional Ti atoms. It was found that one Ti atom increases the charge-density at nuclei of Fe by 0.007 s-like electrons, if present in the nearest-neighbour shell, and by 0.002 s-like electrons, if situated in the next-nearest-neighbour shell. The effect of more distant Ti atoms is the opposite, i.e. they decrease the charge-density, and, consequently, the average effective charge-density at nuclei of Fe atoms hardly changes with Ti content. The estimated change of the charge-density due to one Ti atom per unit cell, eta=0.035, which is by a factor of four to five less than the corresponding figure expected from the Miedema-van der Woude model. On the other hand, the average Fe-site spin-density decreases linearly with Ti content. This fact accompanied by the constant value of the average charge-density can be accounted for by postulating that electrons with spin-up spins flip into the spin-down state. (C) 2002 Elsevier Science B.V. All rights reserved.