Oscillatory Non-collinear Magnetism Induced by Interfacial Charge Transfer in Metallic Oxide Superlattices

Abstract Interfaces between correlated complex oxides are promising avenues to realize new forms of mag-netism that arise as a result of charge transfer, proximity effects and locally broken symmetries.We report upon the discovery of a non-collinear magnetic structure in superlattices of the ferro-magnetic metallic oxide La 2/3 Sr 1/3 MnO 3 (LSMO) and the correlated metal LaNiO (LNO). Theexchange interaction between LSMO layers is mediated by the intervening LNO, such that the an-gle between the magnetization of neighboring LSMO layers varies in an oscillatory manner with thethickness of the LNO layer. The magnetic field, temperature, and spacer thickness dependence ofthe non-collinear structure are inconsistent with the bilinear and biquadratic interactions that areused to model the magnetic structure in conventional metallic multilayers. A model that couplesthe LSMO layers to a helical spin state within the LNO fits the observed behavior. We propose thatthe spin-helix results from the interaction between a spatially varying spin susceptibility withinthe LNO and interfacial charge transfer that creates localized Ni