Synthesis and Characterization of Structural, Thermodynamic, and Magnetic Properties of NaxLi1 – xFeGe2O6 (x = 0.1–0.9) Compounds

Abstract

The properties of NaxLi1 – xFeGe2O6 (x = 0.1–0.9) solid solutions obtained via a solid-phase syn- thesis are measured by X-ray diffraction, calorimetry, and magnetic method. The order–disorder transfor- mations in low-dimensional NaxLi1 – xFeGe2O6 (x = 0.1–0.9) spin systems with predominately antiferromag- netic exchange interaction have been revealed in the low-temperature susceptibility dependences. The study of heat and physical properties confirm that substituting the sodium ions with the lithium ones induces the first-order structural phase transitions of the displacement type which are characterized by a symmetry change in monoclinic crystals from high-temperature C2/c space group to low-temperature P21/c space group.