Spin-lattice coupling across the singular magnetostructural transition in Pr0.5Sr0.5CoO3 by x-ray magnetic circular dichroism

We have performed temperature-dependent x-ray magnetic circular dichroism on ferromagnetic Pr0.5Sr0.5CoO3 at the CoL2,3 edges to analyze the correlation of the spin and orbital angular components of the magnetization with the singular magnetostructural anomalies at ~120 K. We found a sizable orbital angular momentum in Co atoms that follows a temperature dependence very similar to that of the spin momentum. Their sum agrees with the bulk magnetization. Taken together with recent x-ray absorption spectra showing the absence of changes in the electronic filling of Co 3d states across the magnetostructural transition, our results demonstrate the relevance of the spin-orbit coupling for the stabilization of two distinct ferromagnetic phases in this metallic perovskite. The Co spin-state model is discussed on the basis of charge-transfer multiplet calculations of the dichroic spectral shape.