Significant Reduction of the Dead Layers by the Strain Release in La_0.7Sr_0.3MnO₃ Heterostructures

Great efforts have been devoted to exploring the emergent phenomena occurring in heterostructures of correlated oxides. However, the presence of both magnetic and electrical dead layers in functional oxide films generally obstructs the device functionalization and miniaturization. Here, we demonstrate an effective strategy to significantly reduce the thickness of dead layers in a prototypical correlated oxide system, La_0.7Sr_0.3MnO₃ (LSMO) grown on LaAlO₃ (LAO) substrates, via strain engineering by inserting a Sr₃Al₂O₆ buffer layer with a different thickness at heterointerfaces. In this way, the thicknesses of the magnetic and electrical dead layers of LSMO films on the LAO substrates notably decrease from 8 to 4 unit cells and from 13 to 9 unit cells, respectively. Our results provide a convenient method to minimize or even eliminate the dead layers of correlated oxides through the interfacial strain engineering, which has potential applications in nanoscale oxide spintronic devices.