Journal article
A. Auslender, Adham Basha, D. Grave, A. Rothschild, O. Diéguez, A. Kohn
Microscopy and Microanalysis, 2023
Microscopy and Microanalysis, 2023
Semantic Scholar
DOI
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APA
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Auslender, A., Basha, A., Grave, D., Rothschild, A., Diéguez, O., & Kohn, A. (2023). The Mean Inner Potential of Hematite α-Fe2O3 Across the Morin Transition. Microscopy and Microanalysis.
Chicago/Turabian
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Auslender, A., Adham Basha, D. Grave, A. Rothschild, O. Diéguez, and A. Kohn. “The Mean Inner Potential of Hematite α-Fe2O3 Across the Morin Transition.” Microscopy and Microanalysis (2023).
MLA
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Auslender, A., et al. “The Mean Inner Potential of Hematite α-Fe2O3 Across the Morin Transition.” Microscopy and Microanalysis, 2023.
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@article{a2023a,
title = {The Mean Inner Potential of Hematite α-Fe2O3 Across the Morin Transition},
year = {2023},
journal = {Microscopy and Microanalysis},
author = {Auslender, A. and Basha, Adham and Grave, D. and Rothschild, A. and Diéguez, O. and Kohn, A.}
}
Abstract
We measure the mean inner potential (MIP) of hematite, α-Fe2O3, using electron holography and transmission electron microscopy. Since the MIP is sensitive to valence electrons, we propose its use as a chemical bonding parameter for solids. Hematite can test the sensitivity of the MIP as a bonding parameter because of the Morin magnetic phase transition. Across this transition temperature, no change in the corundum crystal structure can be distinguished, while a change in hybridized Fe-3d and O-2p states was reported, affecting ionic bonding. For a given crystallographic phase, the change in the MIP with temperature is expected to be minor due to thermal expansion. Indeed, we measure the temperature dependence in corundum α-Al2O3(112¯0) between 95 and 295 K showing a constant MIP value of ∼16.8 V within the measurement accuracy of 0.45 V. Thus, our objectives are as follows: measure the MIP of hematite as a function of temperature and examine the sensitivity of the MIP as a bonding parameter for crystals. Measured MIPs of α-Fe2O3(112¯0) above the Morin transition are equal, 17.85 ± 0.50 V, 17.93 ± 0.50 V, at 295 K, 230 K, respectively. Below the Morin transition, at 95 K, a significant reduction of ∼1.3 V is measured to 16.56 ± 0.46 V. We show that this reduction follows charge redistribution resulting in increased ionic bonding.
