Abstract
There is an apparent mismatch between electron paramagnetic resonance and Mössbauer spectroscopy results on the charge and spin states of dilute Fe impurities in NaCl; Mössbauer spectroscopy data have been interpreted in terms of high-spin Fe2+, while electron paramagnetic resonance studies suggest low-spin Fe1+. In the present study, the charge and spin states of dilute substitutional Fe impurities in NaCl and LiF have been investigated with Mn57?Fe57 emission Mössbauer spectroscopy. A scheme is proposed which takes into account the effects of nearest-neighbor distances and electronegativity difference of the host atoms on the Mössbauer isomer shift and allows for the unequivocal differentiation between high-spin Fe2+ and high/low-spin Fe1+ in Mössbauer spectroscopy. From these considerations, the Mössbauer results are found to be consistent with dilute Fe impurities in NaCl and LiF in a low-spin Fe1+ state. These conclusions are supported by theoretical calculations of isomer shifts and formation energies based on the density-functional theory. The experimental results furthermore suggest that charge compensation of dilute Mn2+ dopants in NaCl and LiF is achieved by Na vacancies and F- interstitials, respectively.
| Original language | English |
|---|---|
| Article number | 174108 |
| Journal | Physical Review B |
| Volume | 106 |
| Issue number | 17 |
| DOIs | |
| Publication status | Published - 1 Nov 2022 |
Bibliographical note
Funding Information:We acknowledge the support of the ISOLDE Collaboration and technical teams and cluster resources provided by CERN (HTC/Condor). G. Marschick (Vienna University of Technology, Austria; University Duisburg-Essen, Germany & CERN, Switzerland) is acknowledged for experimental help. B. Qi (University of Iceland, Iceland) is acknowledged for fruitful discussions. S.O. acknowledges support from the University of Iceland Research Fund. R.A. acknowledges the funding of the Austrian Science Fund (FWF) through Projects No. P26830 and No. P31423. The Federal Ministry of Education and Research (BMBF) through Grants No. 05K16PGA and No. 05K19SI1 “eMMA” is acknowledged. The European Commission through the Horizon 2020 programme (Grant No. 654002, ENSAR 2) is acknowledged. K.B.-R., H.M., D.N., K.N., and G.P. acknowledge support of the Department of Science & Innovation (South Africa) within the SA-CERN Program. I.U. acknowledges the support of the Ministry of Economy and Competitiveness (MINECO/FEDER) under Project No. RTI2018-094683-B-C55 and Basque Government Grant No. IT-1500-22.
Publisher Copyright:
© 2022 authors. Published by the American Physical Society. Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.