TY - JOUR
T1 - Magnetic structure of oxygen-deficient perovskite nickelates with ordered vacancies
AU - Shin, Yongjin
AU - Rondinelli, James M.
N1 - Funding Information:
Y.S. and J.M.R. acknowledge support from the National Science Foundation (NSF) under Award No. DMR-2011208. Calculations were performed using the QUEST HPC Facility at Northwestern, the Extreme Science and Engineering Discovery Environment (XSEDE), 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 U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
Publisher Copyright:
© 2022 authors. Published by the American Physical Society.
PY - 2022/6
Y1 - 2022/6
N2 - The oxygen vacancy concentration in LaNiO3-δ nickelate perovskites affects magnetic interactions and long-range magnetic order through changes in local electronic configurations, crystal field splitting energies, and polyhedral arrangements. Here we use density functional theory calculations to examine the magnetic structure of LaNiO2.5 and LaNiO2.75 with structural ordered oxygen vacancies (OOV). These OOV phases exhibit columnar arrangements of NiO4 square planar units, which adopt low-spin Ni2+ (d8) configurations with nominally zero magnetic moment (S=0), interconnected by NiO6 octahedral units. The magnetic structure of the OOV phases are governed by the flexible charge state of the NiO6 octahedral units, whose density and connectivity depends on the oxygen vacancy concentration. LaNiO2.5 is stable in an insulating A-type antiferromagnetic (AFM) phase derived from octahedral units comprising Ni2+ in AFM chains. LaNiO2.75 is a narrow-gap insulator with zigzag-type AFM order originating from weakly localized electrons in columnar breathing distortions to the NiO6 units. Our results suggest that nanoscale OOV phases within single-phase LaNiO3-δ crystals can account for its reported complex magnetic ground-state structure.
AB - The oxygen vacancy concentration in LaNiO3-δ nickelate perovskites affects magnetic interactions and long-range magnetic order through changes in local electronic configurations, crystal field splitting energies, and polyhedral arrangements. Here we use density functional theory calculations to examine the magnetic structure of LaNiO2.5 and LaNiO2.75 with structural ordered oxygen vacancies (OOV). These OOV phases exhibit columnar arrangements of NiO4 square planar units, which adopt low-spin Ni2+ (d8) configurations with nominally zero magnetic moment (S=0), interconnected by NiO6 octahedral units. The magnetic structure of the OOV phases are governed by the flexible charge state of the NiO6 octahedral units, whose density and connectivity depends on the oxygen vacancy concentration. LaNiO2.5 is stable in an insulating A-type antiferromagnetic (AFM) phase derived from octahedral units comprising Ni2+ in AFM chains. LaNiO2.75 is a narrow-gap insulator with zigzag-type AFM order originating from weakly localized electrons in columnar breathing distortions to the NiO6 units. Our results suggest that nanoscale OOV phases within single-phase LaNiO3-δ crystals can account for its reported complex magnetic ground-state structure.
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U2 - 10.1103/PhysRevResearch.4.L022069
DO - 10.1103/PhysRevResearch.4.L022069
M3 - Article
AN - SCOPUS:85134469642
SN - 2643-1564
VL - 4
JO - Physical Review Research
JF - Physical Review Research
IS - 2
M1 - L022069
ER -