Valence and Magnetic Investigations of Alkali Metal-Doped Europium Sulfide

Abstract

Using europium sesquioxide nanowires as a starting material for the synthesis of europium sulfides, we have discovered alkali metal doping Eu1–xNaxS for the first time. Alkali metal doping stabilizes the NaCl structure type of EuS at surprisingly low temperatures. We investigated the europium valence through XPS and Mössbauer spectroscopy as a function of dopant in Eu1–xNaxS for x = 0–0.5. In addition, based on magnetic studies, the ferromagnetic ordering is diminished by the presence of the nonmagnetic dopant, causing a decrease in the ordering temperature.