Surface and bulk charge distribution in manganese sulfide doped with lanthanide ions

The oxidation state studies of Mn_1-xLn_xS (Ln = Dy, Tm, Yb; x = 0; 0.01; 0.05) solid solutions was carried out for the first time using X-ray photoelectron and emission spectroscopy. The binding energy of the S(2p)-, Ln(4d)-, multiplet splitting analysis of Mn(3s)-level and the SKα₁-line energy position allow one to determine atoms oxidation state. The lanthanide atoms were found to be in the trivalent, while the manganese and sulfur atoms were in the divalent state. The near-surface layers contain sulfur atoms in the 0, +4 and +6 oxidation states. The obtained data on the oxidation state were compared with those in lanthanide sulfides Ln₂S₃ (Ln = Dy, Tm, Yb). The additional 4f-electrons emerged after cationic substitution are assumed to be delocalized in the conduction band and affect physical properties of doped manganese monosulfide. The oxidation state of lanthanide and manganese atoms both on the surface and in the bulk was found to be the same in the compounds studied. The surface layer doesn't contain an additional metal oxidation states (magnetic scattering centers) that significantly affect the colossal magnetoresistance.