Dimensionality driven exchange coupling effect in cuprate-manganite superlattices

Abstract

The coupling and competition between various degrees of freedom at the interface of transition metal oxide heterointerfaces greatly enrich their physical properties and expand their relevant application scope. It has been reported that dimensionality is an effective method to regulate the properties of oxide heterostructure. The structure of SCO film exhibits a planar-type-to-chain-type transformation with the change of thickness. In this work, the high-quality SCO/LCMO superlattices are deposited by a pulsed laser deposition system. And the interfacial exchange coupling effect is effectively manipulated by controlling the dimensionality of SCO layer. X-ray absorption spectrum (XAS) measurement shows that the charge transfer occurs at the heterointerface. When the SCO layer is thin, the interfacial superexchange coupling supported by charge transfer generates a weak magnetic moment to pin the ferromagnetic LCMO layer. As the SCO layer thickens, the charge transfer will decrease. Meanwhile, the long-range antiferromagnetic order in thicken SCO layer can interact with LCMO layer, resulting in the exchange bias effect. This experiment confirms the important role of dimensionality in modulating the properties in multifunctional oxide heterostructure.