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LaNiO3 is a strange metal, for reasons that are not well understood. Here, Liu et al. report evidence for scattering of charge carriers by antiferromagnetic quantum fluctuations in high-purity epitaxial thin films of LaNiO3, suggesting it is close to an antiferromagnetic quantum critical point.

Interfaces between correlated complex oxides are promising avenues to realize new forms of magnetism that arise as a result of charge transfer, proximity effects, and locally broken symmetries. We report on the discovery of a noncollinear magnetic structure in superlattices of the ferromagnetic metallic oxide La_{2/3}Sr_{1/3}MnO_{3} (LSMO) and the correlated metal LaNiO_{3} (LNO). The exchange interaction between LSMO layers is mediated by the intervening LNO, such that the angle between the magnetization of neighboring LSMO layers varies in an oscillatory manner with the thickness of the LNO layer. The magnetic field, temperature, and spacer thickness dependence of the noncollinear structure are inconsistent with the bilinear and biquadratic interactions that are used to model the magnetic structure in conventional metallic multilayers. A model that couples the LSMO layers to a helical spin state within the LNO fits the observed behavior. We propose that the spin-helix results from the interaction between a spatially varying spin susceptibility within the LNO and interfacial charge transfer that creates localized Ni^{2+} states. Our work suggests a new approach to engineering noncollinear spin textures in metallic oxide heterostructures.