Spin reorientation at (110)-La2/3Sr1/3MnO3/LaCoO3 interfaces by orbital/charge reconstruction

The interface reconstruction in perovskite heterostructures caused by interfacial octahedral tilt/rotation and its effects on the spin, charge, and orbital degrees of freedom is a very attractive topic for correlated oxides. Here, we present a systematic investigation on tensely strained (110)-LaCoO3/La2/3Sr1/3MnO3/LaCoO3 trilayers, focusing on orbital reconstruction and accompanied effects. The most remarkable finding is the reordering of the energy levels of Mn-3d orbitals at the interface: the low-lying orbital becomes dx2-y2 for sandwiched La2/3Sr1/3MnO3 rather than d3z2-r2 as expected for a bare La2/3Sr1/3MnO3 film. Interlayer charge transfer via dx2-y2 orbitals is further detected as a driving force of orbital reconstruction. Due to spin–orbit coupling, the charge/orbital reconstruction produces a chain effect on the spin degree of freedom of the La2/3Sr1/3MnO3 layer, resulting in a dramatic spin reorientation by 90° in a film plane. The present work demonstrates how to tune macroscopic properties of correlated oxides via mutual coupling between different degrees of freedom.