Regulating the resistivity of rare-earth nickelates electronic phase transition perovskites via NiO composition

Although rare-earth nickelates (ReNiO3) exhibit widely adjustable metal-to-insulator transition (MIT) properties, it is yet difficult to control their material resistivities to cater for potential applications in correlated electronics. Herein, we demonstrate a strategy to regulate the material resistivities of ReNiO3 while maintaining their relative abrupt MIT properties by compositing with the NiO nanoparticles and afterward high oxygen pressure sintering. Introducing the more insulating NiO as a secondary phase within ReNiO3 (e.g., NdNiO3 and SmNiO3) elevates their material resistivities across two orders of magnitudes while maintaining a similar critical temperature (TMIT) and its resultant resistive change at a moderate compositing ratio (e.g., <80 %). The nearest-neighbors-hopping (NNH) model and linear model were used to fit the low-temperature electric transportation properties for both the insulating and metallic phases of ReNiO3, and it indicates that the pristine carrier transportation modes can be well preserved despite a high compositing ratio of NiO up to 80 %. Similar effects cannot be achieved by using other more insulating compositing oxides, such as BaBiO3, LaAlO3, and NiFe2O4, as the abruption in resistive change across TMIT was not preserved at a similar high compositing ratio (e.g., >20 %), while their carrier transportation modes varied at much smaller composition ratio. It is worth noticing that the compositing with NiO also improves the mechanical strength of ReNiO3, and this benefits their practical applications in electronic devices.