Magnetic oxygen in transition metal oxides: A case study of Ba2CoO4

Zhang, Yubo; Ning, Jinliang; Hou, Lin; Kidd, Jamin; Foley, Melissa M.; Zhang, Jiandi; Jin, Rongying; Sun, Jianwei; Plummer, Ward

doi:10.1016/j.jpcs.2020.109803

Cited by 5 publications

(10 citation statements)

References 33 publications

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“…The very small energy differences between the AF structures suggest that the AF order results from the competition of the various magnetic interactions present in the system. For the AFI structure, the magnetic moment determined by DFT+U (DFT) on each Co is 2.78(2.72) µ B in good agreement with experimental values: 2.69(4) µ B [15], 3.5 µ B [19] and 3.23 µ B [17] and an additional induced moment of ≈ 0.4 µ B is found on each O atoms, in accordance with very recent DFT calculations [16]. Also, moments of the same magnitude are found in all the other magnetic structures considered.…”

supporting

confidence: 88%

“…To explain the large difference between both temperatures, magnetic frustration has been suggested [13,14]. Also, spin dimer analysis with tight binding calculation attributes the origin of the difference in temperature to layered magnetic frustration [14], while alternative analysis of the spin dynamics with inelastic neutron scattering [15] and the very recent DFT studies [16] assert that quasi 2D-magnetism could be realized in non-layered Ba 2 CoO 4 . Hence, there is the need to fully understand the magnetic interactions together with the nature and origin of the probable indirect exchange interaction that * ifeanyijohn.onuorah@unipr.it drives magnetism.…”

mentioning

confidence: 99%

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Frustrated network of indirect exchange paths between tetrahedrally coordinated Co in Ba2CoO4

Onuorah,

Isah,

De Renzi

et al. 2021

Preprint

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We present the study of the electronic and magnetic interactions of Ba2CoO4, structurally unique because of the rare isolated CoO4 distorted tetrahedral coordination. We show that the Co(d)−O(p) hybridized states and 0.4 µB induced spin moment on O play roles in characterizing the existence of oxygen-hole states that stabilize Co in the high spin configuration with full degeneracy lifting by the distorted tetrahedra. The calculated isotropic exchange interaction parameters demonstrate the presence of 3D network of magnetic coupling and our results further provide proof for the indirect exchange mechanism mediated by O atoms via the Co−O• • • O−Co path.

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supporting

confidence: 88%

mentioning

confidence: 99%

Frustrated network of indirect exchange paths between tetrahedrally coordinated Co in Ba2CoO4

Onuorah,

Isah,

De Renzi

et al. 2021

Preprint

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“…Previous theoretical studies provided qualitative explanations about the spin exchange interactions, which was assumed to originate from the "super-super-exchange" mechanism between CoO 4 clusters (namely involving two oxygens as bridge between TM atoms), leading to a BCO zigzag magnetic structure [43]. Recently, another the-oretical work suggested that a simplified super-superexchange is inappropriate for the description of the BCO system, because the magnetic moment of oxygens was also considered to provide a substantial contribution to the total local magnetic moments of each CoO 4 ionic cluster [44]. Furthermore, their density functional theory (DFT) calculations also unveiled another interesting finding: the spin density exhibits a node between O and Co atoms, and a similar phenomenon was also found in SrRuO 3 [28,44].…”

Section: Introductionmentioning

confidence: 99%

“…Recently, another the-oretical work suggested that a simplified super-superexchange is inappropriate for the description of the BCO system, because the magnetic moment of oxygens was also considered to provide a substantial contribution to the total local magnetic moments of each CoO 4 ionic cluster [44]. Furthermore, their density functional theory (DFT) calculations also unveiled another interesting finding: the spin density exhibits a node between O and Co atoms, and a similar phenomenon was also found in SrRuO 3 [28,44].…”

Section: Introductionmentioning

confidence: 99%

“…Finally, simplified one-orbital Hubbard and two-orbital double-exchange models are used to investigate the formation of the long-range zigzag magnetic order and reveal the importance of the easy-axis anisotropies on triangular lattices to alter the balance between the canonical 120 • antiferromagnetic order expected in directional isotropic systems vs. the zigzag order found in BCO and in our calculations. The important issues related to magnetoelastic effects in BCO also unveiled in recent work [44] would require incorporating the lattice in our theory effort, and such studies will be carried out in the future.…”

Section: Introductionmentioning

confidence: 99%

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Oxygen magnetic polarization, nodes in spin density, and zigzag spin order in oxides

Lin,

Kaushal,

Şen

et al. 2021

Preprint

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Recent density functional theory (DFT) calculations for Ba2CoO4 (BCO) and neutron scattering experiments for SrRuO3 (SRO) have shown that oxygen develops a magnetic polarization. Moreover, DFT calculations for these compounds also unveiled unexpected nodes in the spin density, both along Co-O and Ru-O. For BCO, the overall antiferromagnetic state in its triangular lattice contains unusual zigzag spin patterns. Here, using simple model calculations supplemented by DFT we explain and extend these results. We predict that ligands that in principle should be spinless, such as O 2− , will develop a net polarization when they act as electronic bridges between transition metal (TM) spins ferromagnetically ordered, regardless of the number of intermediate ligand atoms. The reason is the hybridization between atoms and mobility of the electrons with spins opposite to those of the closest TM atoms. Moreover, for bonds with TMs antiferromagnetically ordered, counterintuitively our calculations show that oxygens should also have a net magnetization for the super-super-exchange cases TM-O-O-TM while for only one oxygen, as in Cu-O-Cu, the Opolarization should cancel. Our results for the TM antiferromagnetic case are more general: for an even number of ligands between antiparallel TM spins, all ligands will develop nonzero polarization albeit of opposite signs, while for an odd number of ligands only the central one will have zero net polarization while the rest will have a nonzero polarization. Our simple model also allows us to explain the presence of nodes based on the antibonding character of the dominant singly occupied molecular orbitals along the TM-O bonds. Finally, the zigzag pattern order becomes the ground state mainly due to the influence of the Hubbard U , that creates the moments, in combination with a robust easy-axis anisotropy that suppresses the competing 120 • degree antiferromagnetic order of a triangular lattice. Our predictions are generic and should be applicable to any other compound with characteristics similar to those of BCO and SRO.

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Exploring the efficacy and future potential of polypyrrole/metal oxide nanocomposites for electromagnetic interference shielding: a review

Sood,

Mudila,

Chamoli

et al. 2024

Mater. Horiz.

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Magnetic oxygen in transition metal oxides: A case study of Ba2CoO4

Cited by 5 publications

References 33 publications

Frustrated network of indirect exchange paths between tetrahedrally coordinated Co in Ba2CoO4

Frustrated network of indirect exchange paths between tetrahedrally coordinated Co in Ba2CoO4

Oxygen magnetic polarization, nodes in spin density, and zigzag spin order in oxides

Exploring the efficacy and future potential of polypyrrole/metal oxide nanocomposites for electromagnetic interference shielding: a review

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