NUKLEONIKA 2004, 49(Supplement 3):s63-s65

LOCAL ELECTRONIC AND CHARGE STATE OF IRON IN FeTe2

Jan Stanek1, Piotr Fornal2

1 M. Smoluchowski Institute of Physics, Jagiellonian University, 4 Reymonta Str., 30-059 Kraków, Poland,
2 Institute of Physics, Cracow University of Technology, 1 Podchorążych Str., 30-083 Kraków, Poland

From 57Fe Mössbauer spectrum of FeTe2 taken in high external magnetic field (B = 4.6 T), the sign of electric field gradient was determined as negative, with an asymmetry parameter of 0.2. A comparison of these data with results of calculation of the electric field gradient within point charge model suggests the lattice character of electric field gradient with some contribution from covalency effects. The effective magnetic field acting on 57Fe is less than the applied, which points out the diamagnetic Fe+2 state of iron. This “electronic state” is in a contradiction to Fe+3 “charge state” concluded from 125Te experiments on 3d transition metal ditellurides as well as from 57Fe quadrupole splitting and isomer shift.