Non collinear antiferromagnetic surface on a ferromagnetic manganite

Abstract

Electronic reconstruction at interfaces between different oxides is giving rise to a plethora of new functionalities and novel phenomena. Complex oxides are characterized by a strong interplay of the different degrees of freedom (orbital, spin and lattice) which can be engineered and modified at interfaces and surfaces. In order to get experimental information on these modifications, different surface sensitive probes can be used. In particular, x-ray linear dichroism XLD can be used to get information on the symmetry of the electronic and magnetic properties on a manganite surface. The chosen manganite is the optimal doped La0.7Sr0.3MnO3, which is ferromagnetic in bulk. By studying the XLD results as a function of the angle between the applied magnetic field and the surface, an antiferromagnetic order, non collinear with the bulk ferromagnetic order, is inferred. Theoretical calculations reveal that the observed surface reconstruction is a result of the competition between spin-orbit coupling (enhanced at the interface) and the magnetic double exchange interaction.