The x-ray magnetic circular dichroism spin sum rule for 3d4 systems: Mn3+ ions in colossal magnetoresistance manganites

The colossal magnetoresistance manganites La0.87 +/- 0.02Sr0.12 +/- 0.02MnO3+delta, La0.78 +/- 0.02Sr0.17 +/- 0.02MnO3+delta, and La0.66 +/- 0.02Sr0.36 +/- 0.02MnO3+delta (delta close to 0) were investigated by using soft x-ray magnetic circular dichroism (XMCD) and magnetometry. Very good agreement between the values for the average Mn magnetic moments determined with these two methods was achieved by correcting the XMCD spin sum rule results by means of charge transfer multiplet calculations, which also suggest a charge transfer of similar to 50% for Mn4+ and similar or equal to 30% for Mn3+. The magnetic moment was found to be localized at the Mn ions for x = 0.17 and 0.36 at 80 K and for x = 0.12 in the temperature range from 80 to 300 K. We discuss our findings in the light of previously published data, confirming the validity of our approach.