Detailed 57Fe M\"ossbauer spectroscopy measurements on superconducting NaFeAs powder crystals have been performed. The 57Fe spectra recorded in the paramagnetic temperature range (T > TN \approx 46 +/- 2 K) were discussed supposing Fe2+ ions are located in distorted tetrahedral (FeAs4) polyhedra. Our results reveal that the structural transition (TS \approx 55 K) has a weak effect on the electronic structure of iron atoms while the development of the antiferromagnetic order (T =< TN) induces a redistribution of the charge at 57Fe nuclei. In the low-temperature range, the spectra show a diffuse resonance absorption structure which evidences for the existence of a continuous distribution of hyperfine fields HFe at 57Fe nuclei. The shape of these spectra can be related to the formation of a microdomain structure or phase separation. Analysis of the resulting distributions p(HFe) has shown that the M\"ossbauer spectra give consistent and physically reasonable 57Fe hyperfine parameters over the whole temperature range.
@article{arxiv.1209.0924,
title = {A 57Fe M\"ossbauer Study Of Local Structure And Spin Arrangements In Antiferromagnetic NaFeAs},
author = {Igor Presniakov and Igor Morozov and Alexey Sobolev and Mariya Roslova and Alexander Boltalin and Vladimir Son and Olga Volkova and Alexander Vasiliev},
journal= {arXiv preprint arXiv:1209.0924},
year = {2015}
}
Comments
This paper has been withdrawn by the author due to conflict of interests