The formation of europium sulfide by the H₂SEu₂O₃ reaction at high temperatures

The Eu2O3-H2S reaction has been studied over the temperature range 350 to 2000°C. The reaction sequence with increasing temperature is Eu2O3 → Eu2O2S → Eu3S4 → EuS. Ferromagnetic EuS is the stable equilibrium phase above 900°C. Oxygen analyses of the resulting phases showed that samples prepared at ∼ 1250° contained the minimum concentration of oxygen as an impurity (> 75 PPM). The growth of EuS single crystals using low oxygen content starting material is described and the physical properties summarized. © 1972.