Phase engineering of rare earth nickelates by digital synthesis

Abstract

We report on the electronic and magnetic properties of a series of [m EuNiO3/p LaNiO3] superlattices (thickness m and/or p = 1 unit cell) epitaxially grown on single crystalline NdGaO3 substrates. The structural symmetry of these films has been investigated by the combination of in-situ reflection high energy electron diffraction and X-ray diffraction measurements. The metal-insulator transition and the magnetic transition temperatures of the short-period superlattices with m ≥ p are modified from the corresponding bulk Eu1–xLaxNiO3 (x=pm+p) composition. In contrast to the corresponding bulk doped compound with x = 0.67, the [1 EuNiO3/2 LaNiO3] film remains metallic down to at least 2 K without signs of electronic or magnetic transitions. These findings demonstrate the power of the digital synthesis approach to realize electronic and magnetic phases of perovskite nickelates, unattainable in bulk.