Experimental Testing of the Theoretically Predicted Magnetic Properties for Kagomé Compounds in the Li-Fe-Ge System

Investigating material properties is essential to assessing their application potential. While computational methods allow for a fast prediction of the material structure and properties, experimental validation is essential to determining the ultimate material potential. Herein, we report the synthesis and experimental magnetic properties of three previously reported Kagome compounds in the Li-Fe-Ge system. LiFe₆Ge₄, LiFe₆Ge₅, and LiFe₆Ge₆ were predicted to have ferromagnetic or antiferromagnetic ground states. The hydride route that replaces the ductile Li metal with salt-like LiH proved to be an excellent alternative for the facile synthesis of the Li-Fe-Ge powders with appreciable purity, permitting the investigation of their bulk magnetic properties. Magnetometry below room temperature and room-temperature ⁵⁷Fe Mössbauer spectroscopy collectively indicate an antiferromagnetic ground state for the three compounds with ordering temperatures above 300 K, contrary to the prediction of ferromagnetic ground states. Moreover, Mössbauer spectroscopy reveals a magnetization of 1.1-1.3 μ_B/Fe atom for the Li-Fe-Ge compounds, while higher moments of 1.63-2.90 μ_B/Fe atom were theoretically predicted. Experimental (in)validation addresses the issue of inaccuracy in determining material properties in silico only and helps to improve the prediction power of the computational models. This work underlines that the contribution of experimentalists continues to be valuable for the accurate determination of structure-property relationships in solid-state materials.