XPS study in CeAg and EuCu2Si2 at low temperatures down to 4 K

Abstract Electronic structure of CeAg and EuCu 2 Si 2 was investigated by XPS measurements in a temperature range from 3.7 to 300 K. When the temperature was decreased, the mixing ratio of Eu 3+ /Eu 2+ in EuCu 2 Si 2 was increased, showing a maximum near 50 K and then decreased.