Site occupancies in the R2-xFe14+2xSi3

(R = Ce, Nd, Gd, Dy, Ho, Er, Lu, Y) compounds studied by Mössbauer spectroscopy

A. Błachowski 1, K. Ruebenbauer 1, J. Przewoźnik 2, J. Żukrowski 2, D. Sitko 3, N.-T.H. Kim-Ngan 3, A.V. Andreev 4

1 Mössbauer Spectroscopy Division, Institute of Physics, Pedagogical University, Kraków, Poland

2 Solid State Physics Department, Faculty of Physics and Applied Computer Science,

AGH University of Science and Technology, Kraków, Poland

3 Surface Physics Division, Institute of Physics, Pedagogical University, Kraków, Poland

4 Institute of Physics, Academy of Sciences, Prague, Czech Republic

R2Fe17

R2Fe14Si3

Y Ce Nd Sm Gd Tb Dy Ho Er Tm Lu

Crystal structure

4 + 1(?) iron crystallographic positions

R2-xFe14+2xSi3

Iron hyperfine sites

7 + 1(?)iron magnetic positions

X-ray powder diffraction

Crystallographic Magnetic

R2-xFe14+2xSi3

Regular iron site occupanciesContribution (at. % Fe)

Ce Nd Gd Dy Ho Er Lu Y

C

ontr

ibut

ion

(at.

% F

e)

mmcPmR /6 3 3

6c 4f

9d 6g

18f or 18h 12j or 12k

18h or 18f 12k or 12j

R2-xFe14+2xSi3

Non-stoichiometry parameter2x

Ce Nd Gd Dy Ho Er Lu Y

R2-xFe14+2xSi3

Conclusions

Si atoms avoid

6c (4f) and 9d (6g) sites for R3m (P63/mmc) structure.

Fe atoms partly replace R atoms

on 6c-R (2b) sites for R3m (P63/mmc) structure forming 12e (4e) dumbbells.

Non-stoichiometry parameter

x = 0.25(5) for all compounds investigated.