Crossover behavior seen in symmetries of rare earth nickelate solutions
DOI: 10.1063/10.0005844
Crossover behavior seen in symmetries of rare earth nickelate solutions lead image
Perovskite oxide are a large family of materials with physical properties ranging from superconductivity to ferroelectricity due to their flexible lattice structure. These materials can be subtly tuned to enhance specific characteristics, making them of interest to new material design.
Fowlie et al. delve into the symmetries of rare earth perovskites oxides with a study of neodymium nickel (III) oxide and lanthanum nickel oxide thin film solutions. These nickelate materials have distinct space-groups but the same perovskite structure. The authors investigated how symmetry transitions occur in a solution where lanthanum replaces neodymium.
Using Raman spectroscopy, which allowed a look at the symmetries and phase transitions, and scanning transmission electron microscopy, to investigate the atomic-scale evolution, the authors analyzed the transition in solid solution thin films of the materials. Unexpectedly, the results showed not a true crossover but two coexisting symmetries during the evolution between phases.
“From the Raman spectroscopy, it looked like the two series of samples were identical,” said co-author Jennifer Fowlie. “It was only when we used scanning transmission electron microscopy to really look at an atomic level that we saw it’s actually not so similar between the two systems. In the end, we needed both Raman spectroscopy and STEM to see the full picture.”
The symmetry differences seemed to depend on the substrate used and the way the film is grown, among other variables. The authors would like to continue studying characteristics of such materials. Different electric and magnetic behaviors might be expected in the unique symmetry groups as they might affect the bond angle and bond lengths.
These findings may ultimately help in future development of perovskite oxide material design.
Source: “Crossover between distinct symmetries in solid solutions of rare earth nickelates,” by Jennifer Fowlie, Bernat Mundet, Constance Toulouse, Alexander Schober, Mael Guennou, Claribel Domínguez, Marta Gibert, Duncan T. L. Alexander, Jens Kreisel, and Jean-Marc Triscone, APL Materials (2021). The article can be accessed at https://doi.org/10.1063/5.0057216 .
