Charge Transfer and Structural Anomaly in Stoichiometric Layered Perovskite Sr2Co0.5Ir0.5O4

Daria Mikhailova*, Zhiwei Hu, Chang Yang Kuo, Steffen Oswald, Kailash M. Mogare, Stefano Agrestini, Jyh Fu Lee, Chin Wen Pao, Shin An Chen, Jenn Min Lee, Shu Chih Haw, Jin Ming Chen, Yen Fa Liao, Hirofumi Ishii, Ku Ding Tsuei, Anatoliy Senyshyn, Helmut Ehrenberg

*此作品的通信作者

研究成果: Article同行評審

16 引文 斯高帕斯(Scopus)

摘要

A layered Sr2Co0.5Ir0.5O4(space group I4/mmm) perovskite of the K2NiF4structure type was synthesized as a single-phase sample. Neutron powder diffraction measurements revealed full site occupancy of oxygen atoms. The Co3+/Ir5+valence states were evaluated by a combination of X-ray absorption and X-ray photoemission spectroscopy as well as by magnetization measurements, and thus the differences to the parent compounds Sr2CoO4and Sr2IrO4with similar structures were confirmed. Co-K edge EXAFS studies indicated a long average Co–O distance of 1.967 Å suggesting a high-spin state of the Co3+ion in Sr2Co0.5Ir0.5O4. No long-range magnetic ordering down to 4 K was detected by neutron powder diffraction, probably hindered by the random distribution of Co and Ir cations in the Sr2Co0.5Ir0.5O4structure. High-pressure synchrotron powder diffraction studies showed stability of the Sr2Co0.5Ir0.5O4structure up to at least 27 GPa at room temperature. A maximum in the c/a ratio at 10 GPa together with an anomaly in the pressure dependence of the unit-cell volume could be a sign of a change in the spin state of the Co ions under pressure.

原文English
頁(從 - 到)587-595
頁數9
期刊European Journal of Inorganic Chemistry
2017
發行號3
DOIs
出版狀態Published - 2017

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