Na2MnGe2Se6: a new Mn-based antiferromagnetic chalcogenide with large Mn Mn separationCCDC 1471635 & Crystallographic data in CIF format for Na2MnGe2Se6. For crystallographic data in CIF or other electronic format see DOI: 10.1039/c6tc03825e

• Main Authors: Zhou, Molin, Yin, Wenlong, Liang, Fei, Mar, Arthur, Lin, Zheshuai, Yao, Jiyong, Wu, Yicheng
• Format: Article
• Language: English
• ISSN: 2050-7526; 2050-7534
• DOI: 10.1039/c6tc03825e

A new one-dimensional (1D) Mn-based chalcogenide Na 2 MnGe 2 Se 6 has been obtained by a solid-state reaction. It crystallizes in the tetragonal space group I 4/ mcm with unit cell parameters a = 7.7718(16) Å, b = 7.7718(16) Å, c = 19.077(7) Å and Z = 2. In the structure, MnSe 4 and GeSe 4 tetrahedra are linked alternately via edge-sharing with a ratio of 1 : 2 to form 1D infinite [MnGe 2 Se 6 ] 2− anionic chains, which are further separated by Na + cations. Such a spatial arrangement leads to large separations between magnetic ions, namely, 9.538(5) Å for the nearest intrachain Mn Mn distance and 5.495(5) Å for the neighboring interchain Mn Mn distance. Despite the large Mn Mn separation, the temperature dependent susceptibility measurement and specific heat measurement still indicate an interesting antiferromagnetic interaction with the Néel temperature T N = 11 K for this compound. Such unusual magnetic properties have been seldom reported in other Mn chalcogenides. The magnetic interaction is investigated by the spin-polarized calculations. Besides, the UV-vis-NIR spectroscopy measurement indicates that Na 2 MnGe 2 Se 6 has an indirect band gap of 1.93 eV. Despite the large spatial separation of Mn Mn ions, Na 2 MnGe 2 Se 6 still exhibits an interesting antiferromagnetic transition.