Spin- and charge density oscillations around Ir impurity in alpha-Fe studied by Fe Mossbauer spectroscopy

Random solution of iridium in ferromagnetic alpha-Fe of the BCC structure has been investigated by means of the 14.4 keV Mossbauer transition in 57Fe at room temperature. Iridium has been randomly substituted on the iron sites with the concentration up to 11 at.%. Contributions to the hyperfine field and isomer shift on the iron nuclei have been determined as the function of the distance between iron nucleus and iridium impurity up to the third co-ordination shell. Iridium atom as the nearest iron neighbor changes iron hyperfine field by +0.66 T, as the second neighbor makes change by -1.88 T and finally as the third neighbor changes the field by +0.70 T. Corresponding changes in the isomer shift are as follows: -0.031, +0.003 and +0.033 mm/s. Hence, it was found that iridium atoms lead to the very strong oscillations in the spin- and charge density around themselves in the alpha-Fe BCC structure.