The field of oxide spintronics can strongly benefit from the establishment of ferromagnetic insulators with near room-temperature Curie temperature. Here, we investigate the structural, electronic, and magnetic properties of epitaxially strained thin films of the double perovskite La2NiMnO6 (LNMO) grown by off-axis radio-frequency magnetron sputtering. We find that the films retain insulating behavior and a bulk-like Curie temperature in the order of 280 K independently of the epitaxial strain conditions. These results suggest a prospective implementation of LNMO films in multi-layer device architectures where a high-temperature ferromagnetic insulating state is a prerequisite.
A strong coupling of the lattice to functional properties is observed in many transition metal oxide systems, such as the ABO3 perovskites. In the quest for tailor-made materials, it is essential to be able to control the structural properties of the compound(s) of interest. Here, thin film solid solutions that combine NdNiO3 and LaNiO3, two materials with the perovskite structure but distinct space groups, are analyzed. Raman spectroscopy and scanning transmission electron microscopy are combined in a synergistic approach to fully determine the mechanism of the structural crossover with chemical composition. It is found that the symmetry transition is achieved by phase coexistence in a way that depends on the substrate selected. These results carry implications for analog-tuning of physical properties in future functional materials based on these compounds.
Nanoscale mapping
of the distinct electronic phases characterizing
the metal–insulator transition displayed by most of the rare-earth
nickelate compounds is fundamental for discovering the true nature
of this transition and the possible couplings that are established
at the interfaces of nickelate-based heterostructures. Here, we demonstrate
that this can be accomplished by using scanning transmission electron
microscopy in combination with electron energy-loss spectroscopy.
By tracking how the O
K
and Ni
L
edge fine structures evolve across two different NdNiO
3
/SmNiO
3
superlattices, displaying either one or two metal–insulator
transitions depending on the individual layer thickness, we are able
to determine the electronic state of each of the individual constituent
materials. We further map the spatial configuration associated with
their metallic/insulating regions, reaching unit cell spatial resolution.
With this, we estimate the width of the metallic/insulating boundaries
at the NdNiO
3
/SmNiO
3
interfaces, which is measured
to be on the order of four unit cells.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.