Magnetic Ordering and Structural Transition in the Ordered Double-Perovskite Pb2NiMoO6

Jianfa Zhao, Xiao Wang, Xi Shen, Christoph J. Sahle, Cheng Dong, Hajime Hojo, Yuki Sakai, Jun Zhang, Wenmin Li, Lei Duan, Ting Shan Chan, Chien Te Chen, Johannes Falke, Cheng En Liu, Chang Yang Kuo, Zheng Deng, Xiancheng Wang, Richeng Yu, Runze Yu, Zhiwei HuMartha Greenblatt, Changqing Jin*

*此作品的通信作者

研究成果: Article同行評審

摘要

The B-site-ordered double-perovskite Pb2NiMoO6 was prepared at high pressure and high temperature. The structural analysis of synchrotron powder X-ray diffraction data shows that Pb2NiMoO6 crystallizes into monoclinic symmetry with the space group Pc (no. 7), where the Ni and Mo ions are ordered in a rock-salt-type manner. The magnetic and specific heat characterizations reveal unusual two-step antiferromagnetic (AFM) transitions at 18 and 26 K for Pb2NiMoO6. The X-ray absorption spectra at the Ni-L2,3 edge and the Mo-L3 edge and the high-resolution partial fluorescence yield at the Pb-L3 edge indicate Pb2+2Ni2+Mo6+O6 valence states. Although in A2NiMoO6 (A = Sr2+, Pb2+, and Ba2+), the size of the A cation increases gradually from Sr2+ (1.44 Å) to Pb2+ (1.49 Å) to Ba2+ (1.61 Å), Pb2NiMoO6 exhibits much lower symmetry structure and AFM transition temperature, TN, compared with Sr2NiMoO6 (I4/m, TN = 81 K) and Ba2NiMoO6 (Fm3¯ m, TN = 64 K), which is attributed to the large distortion of NiO6 and MoO6 octahedra induced by the lone pair electron effect of Pb2+ with a 6s2 electronic configuration. Moreover, symmetry-breaking phase transition from a high-temperature centrosymmetric, cubic Fm3¯ m phase to a low-temperature non-centrosymmetric, monoclinic Pc phase was observed at 393-413 K in Pb2NiMoO6.

原文English
頁(從 - 到)97-106
頁數10
期刊Chemistry of Materials
34
發行號1
DOIs
出版狀態Published - 11 1月 2022

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