Abstract
The presence of ordered oxygen vacancies in perovskites governs magnetic phase stability owing to changes in crystal-field splitting with different anion geometries, polyhedral arrangements, and electronic configurations of the transition-metal cations. Here we use density functional theory calculations to assess the magnetic phase stability of Sr2Fe2O5 (with a d5 electronic configuration) and Sr2Mn2O5 (d4 configuration), exhibiting the Ca2Mn2O5-type oxygen-deficient perovskite structure, with hydrostatic pressure. The Ca2Mn2O5-type structure is composed of square pyramidal units, the crystal-field splitting and polyhedral connectivities of which support different ground-state magnetic orders depending on d-orbital filling: E-type antiferromagnetic (AFM-E) for Sr2Mn2O5 (d4) and G-type antiferromagnetic (AFM-G) for Sr2Fe2O5 (d5). We show that hydrostatic pressure enhances the crystal-field splitting and affects the magnetic stability. We find that the AFM-E order exhibited by Sr2Mn2O5 is robust over the surveyed ranges of applied pressures, whereas Sr2Fe2O5 shows a magnetic transition from AFM-G to ferromagnetic spin order at ≈24.5 GPa. We also discuss the effect of correlation strength, treated using the Hubbard U correction, which we find suppresses a spin crossover transition in Sr2Fe2O5 and shifts it to higher pressures.
| Original language | English (US) |
|---|---|
| Article number | 104426 |
| Journal | Physical Review B |
| Volume | 102 |
| Issue number | 10 |
| DOIs | |
| State | Published - Sep 2020 |
Funding
Y.S. and J.M.R. acknowledge support from the National Science Foundation under Grants No. DMR-1454688 and No. DMR-2011208. We also thank Dr. Danilo Puggioni for helpful discussion. Calculations were performed using the QUEST HPC Facility at Northwestern University; the Extreme Science and Engineering Discovery Environment, which is supported by the National Science Foundation under Grant No. ACI-1548562; and the Center for Nanoscale Materials (Carbon) Cluster, an Office of Science user facility supported by the US Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics