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Free keywords:
Binary alloys, Niobium, X ray photoelectron spectroscopy, 4f state, Atomic disorder, Core-level spectra, Degree of localization, Electronic.structure, Hard X-ray photoelectron spectroscopy, Hybridisation, Localised, Valence band spectra, Electronic structure
Abstract:
We investigated the electronic structure of BaEu2Nb5O15 and Eu3Nb5O15 by means of hard x-ray photoelectron spectroscopy. The Eu 3d core level spectra are primarily dominated by Eu2+ signals. The well-screened feature in the Nb 3d core level spectra of BaEu2Nb5O15 is suppressed in Eu3Nb5O15, consistent with the insulating behavior of Eu3Nb5O15 due to the atomic disorder and/or the rattling effect of the small Eu ions in the spacious A2 site. In the valence band spectra, the Nb 4d states at the Fermi level are close to the Eu 4f states located around 2 eV below it. This suggests that the degree of localization of the Nb 4d electrons can be enhanced through the Eu 4f-Nb 4d hybridization with the atomically and magnetically disordered Eu ions at the A2 site. © 2024 American Physical Society.
