The transition between antiferromagnetic order and spin-glass state in layered chalcogenides KFeAgCh2 (Ch = Se, S)

Publication date: Available online 2 February 2019Source: Journal of Solid State ChemistryAuthor(s): Bianbian Wang, Zhongnan Guo, Fan Sun, Jun Deng, Jiawei Lin, Dan Wu, Wenxia YuanAbstractInvestigation on the magnetic interaction in Fe-based ThCr2Si2-type compounds is very important not only for understanding the structure-property relationship in this family but also for exploring the superconducting mechanism in related materials. In this work, we report the synthesis and physical properties of two new Fe-based chalcogenides KFeAgSe2 and KFeAgS2. These two compounds adopt ThCr2Si2-type structure with I4/mmm space group and contain the Fe/Ag mixed occupation in the centre of edge-sharing Fe/AgCh4 tetrahedron (Ch = Se, Te). The lattice parameters are refined to be a = 4.1866(2) Å, c = 13.7731(4) Å and a = 3.9845(3) Å, c = 13.3610(4) Å for KFeAgSe2 and KFeAgS2 respectively. Both two compounds show semiconducting behavior with electrical resistivity increased as the temperature decreased, while the resistivity of KFeAgS2 is much larger (~61 Ω·cm at room temperature) than that of KFeAgSe2 (~2.5 Ω·cm at room temperature). Most interestingly, despite the similar electronic structure of these two compounds, KFeAgSe2 features a long-range antiferromagnetic order below 26 K while KFeAgS2 shows a spin-glass state below 19 K. It is indicated that the long-range magnetic ordering can be suppressed in these ThCr2Si2-type transition metal chalcogenides via compressing th...
Source: Journal of Solid State Chemistry - Category: Chemistry Source Type: research