Meeting a strange metal in heterostructures and thin films of LaNiO₃

The transition metal oxides are host to several ‘strange’ metals whose properties cannot be described within the paradigm of conventional Fermi liquids. Heterostructures incorporating such metals also have properties that are distinct from those found in similar structures using conventional metals. In this talk, I will present our work on epitaxial thin films of LaNiO₃, and superlattices of La_2/3Sr_1/3MnO₃/LaNiO₃ grown using ozone-assisted molecular beam epitaxy. LaNiO₃ is widely believed to be a paramagnetic metal down to the lowest temperatures, the only exception amongst the ReNiO₃ rare earth nickelates. I will describe new insights from transport measurements in LaNiO₃ about the nature of this strange metal. In addition, when LaNiO₃ is placed in proximity with La_2/3Sr_1/3MnO₃, interfacial charge transfer and exchange interactions give rise to striking phenomena, including a non-collinear helical magnetic structure in LaNiO₃. These findings will be situated in the context of our current understanding of LaNiO₃.