Electronic, Orbital, And Spin Reconstructions At The Interface Between Metallic La0.7sr0.3mno3 And Charge-Disproportionated Insulator Srcoo2.5

A strained SrCoO2.5 thin film possesses negative charge transfer energy (Delta) and charge disproportionation. In the La0.7Sr0.3MnO3/SrCoO2.5 heterostructure, it is observed that the interfacial strong covalent bonding increases the value of negative Delta of the SrCoO2.5 layer, while charge transfer from the La0.7Sr0.3MnO3 layer melts the charge disproportionation in the SrCoO2.5 layer. Strain-stabilized c-axis orbital polarization is observed in the interfacial Mn/Co ions of the heterostructure. The Co 3d orbital reconstruction is found in the heterostructure due to the strong covalent bond created between the Co 3d and Mn 3d orbitals at the interface. The antiferromagnetic coupling between the Mn and Co ions is observed at the interface of ferromagnetic La0.7Sr0.3MnO3 and SrCoO2.5 layers, which is envisaged from the interfacial Mn/Co orbital polarization and molecular orbital picture. Importantly, such antiferromagnetic coupling observed at room temperature will be very helpful in energy-efficient spintronic applications. The antiferromagnetic interaction at the interfacial region between the ferromagnetic layers produces the exchange-bias effect in the heterostructure. Our result demonstrates valuable insight into the correlation between the electronic states and the magnetic interactions in the artificially intricated heterostructure containing charge-disproportionated insulator and metal to investigate novel interfacial phenomena in other such heterostructures and superlattices.