| Autor: |
Converse, Elizabeth Sobalvarro, Li, Jun, Mullins, Austin C., LaBarre, Patrick G., Ramirez, Arthur P., Subramanian, M. A. |
| Zdroj: |
Inorganic Chemistry; October 2020, Vol. 59 Issue: 19 p14141-14151, 11p |
| Abstrakt: |
Solid solutions with the formula of Bi2–xA′xRu2O7–y(A′ = Mg, Ca, Sr; 0 ≤ x≤ 0.2 for Mg, 0 ≤ x≤ 1 for Ca, and 0 ≤ x≤ 0.5 for Sr) have been synthesized and characterized. The crystal structures for these phases are found to be in the pyrochlore family, crystallizing in the cubic space group Fd3̅mwith complex A/A′ cation coordination environments. The Bi cation is found to be off-center from the ideal position because of a lone-pair distortion, while the positions of the substituted A′ cations vary based on the size and ionicity. The neutron structure refinements reveal a similar propensity to off-center regarding Ca and Sr, while Mg features the largest static displacement of up to 0.48 Å. Interestingly, this is one of only two known pyrochlores with Mg2+located in an 8-coordinated site. The average Ru oxidation state for each substitution is found to increase, and charge compensates for the lower divalent A′ substitution. The solid solutions show temperature-independent resistance across the series with small changes in magnitude that scale with the amount of substitution, while displaying Pauli paramagnetic behavior throughout. |
| Databáze: |
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