High-Pressure Synthesis of Two Polymorphic HgMnO3 Phases and Distinct Magnetism from 2D to 3D

Bowen Zhou; Shijun Qin; Teng Ma; Xubin Ye; Jia Guo; Xiaohui Yu; Hong-Ji Lin; Chien-Te Chen; Zhiwei Hu; Liu-Hao Tjeng; Guanghui Zhou; Cheng Dong; Youwen Long

doi:10.1021/acs.inorgchem.9b03551

High-Pressure Synthesis of Two Polymorphic HgMnO₃ Phases and Distinct Magnetism from 2D to 3D

Inorg Chem. 2020 Mar 16;59(6):3887-3893. doi: 10.1021/acs.inorgchem.9b03551. Epub 2020 Mar 3.

Authors

Bowen Zhou^{1

2}, Shijun Qin^{1

2}, Teng Ma¹, Xubin Ye^{1

2}, Jia Guo^{1

2}, Xiaohui Yu^{1

2}, Hong-Ji Lin³, Chien-Te Chen³, Zhiwei Hu⁴, Liu-Hao Tjeng⁴, Guanghui Zhou⁵, Cheng Dong^{1

2}, Youwen Long^{1

2

6}

Affiliations

¹ Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
² School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China.
³ National Synchrotron Radiation Research Center, 101 Hsin-Ann Road, Hsinchu 30076, Taiwan, ROC.
⁴ Max Planck Institute for Chemical Physics of Solids, Dresden 01187, Germany.
⁵ Department of Physics and Synergetic Innovation Center for Quantum Effects and Applications of Hunan, Hunan Normal University, Changsha 410081, China.
⁶ Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China.

PMID: 32125835
DOI: 10.1021/acs.inorgchem.9b03551

Abstract

An ilmenite-like monoclinic phase of HgMnO₃ with space group P2₁/c was prepared using high-pressure and high-temperature methods at 18 GPa and 1473 K. The MnO₆ octahedra form a two-dimensional (2D) network in the bc plane, leading to a long-range antiferromagnetic ordering with a low Néel temperature of T_N ∼ 32 K. As the synthesis pressure increases to 20 GPa, a new perovskite-like rhombohedral phase with space group R3̅c was found to occur. The rhombohedral phase exhibits a three-dimensional (3D) network for the MnO₆ octahedra, giving rise to an antiferromagnetic ordering at T_N ∼ 60 K. X-ray absorption spectroscopy confirms the invariable Mn⁴⁺ charge state in these two polymorphic phases, in agreement with the Curie-Weiss and bond valence sum analysis. HgMnO₃ provides an interesting example to study the magnetic properties from 2D to 3D by varying synthesis pressure.