Local electronic structure and magnetic properties of LaMn0.5Co0.5O3 studied by x-ray absorption and magnetic circular dichroism spectroscopy

We have studied the local electronic structure of LaMn0.5Co0.5O3 using soft-x-ray absorption spectroscopy at the Co-L-3,L-2 and Mn-L-3,L-2 edges. We found a high-spin Co2+-Mn4+ valence state for samples with the optimal Curie temperature. We discovered that samples with lower Curie temperatures contain low-spin nonmagnetic Co3+ ions. Using soft-x-ray magnetic circular dichroism, we established that the Co2+ and Mn4+ ions are ferromagnetically aligned. We also revealed that the Co2+ ions have a large orbital moment: morb/mspin approximate to 0.47. Together with model calculations, this suggests the presence of a large magnetocrystalline anisotropy in the material and predicts a nontrivial temperature dependence for the magnetic susceptibility.