Orbital occupation, atomic moments, and magnetic ordering at interfaces of manganite thin films

Abstract

We have performed x-ray linear and circular magnetic dichroism experiments at the $\text{Mn}{L}_{2,3}$ edge of the ${\text{La}}_{0.7}{\text{Sr}}_{0.3}{\text{MnO}}_3$ ultrathin films. Our measurements show that the antiferromagnetic (AF) insulating phase is stabilized by the interfacial rearrangement of the $\text{Mn}3d$ orbitals, despite the relevant magnetostriction anisotropic effect on the double-exchange ferromagnetic (FM) metallic phase. As a consequence, the Mn atomic magnetic-moment orientation and how it reacts to strain differ in the FM and AF phases. In some cases a FM insulating (FMI) phase adds to the AF and FM. Its peculiar magnetic properties include in-plane magnetic anisotropy and partial release of the orbital moment quenching. Nevertheless the FMI phase appears little coupled to the other ones.