Fluctuations of the Multiplicity of Co3+ Ions and Softening of the Phonon Spectrum of Rare-Earth Cobalt Oxides

Orlov, Yu. S.; Дудников, В. А.; Sokolov, A. E.; Ovchinnikova, T. M.; Shestakov, N. P.; Овчинников, С. Г.

doi:10.1134/s0021364022100575

Cited by 4 publications

(2 citation statements)

References 21 publications

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“…Stability of the cubic phase of magnetite is a result of the complex mechanism of electron-phonon interaction that is known to have special features in strongly-correlated oxides [58,59] and is activated in magnetite at above T V . Currently, there is neither a complete theoretical description of this mechanism, nor the possibility to study it numerically using first-principles modeling (e.g.…”

Section: Discussionmentioning

confidence: 99%

Frenkel pair formation energy for cubic Fe₃O₄ in DFT + U calculations

Шутикова¹,

Stegaĭlov²

2022

J. Phys.: Condens. Matter

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The cubic phase of magnetite is stabilized above the Verwey transition temperature of about 120~K via a complex electron-phonon interaction that is still not very well understood. In this work using the DFT+U method we describe our attempt to calculate point defect formation energies for this cubic phase in the static approximation. The electronic structure calculations and atomic relaxation peculiarities are discussed in this context. Only the cubic phase model with a small band gap and charge disproportionation (Fe$^{2+}$/ Fe$^{3+}$) gives an adequate point defect formation energies, not the semi-metallic model. The relaxation of the local defect atomic structure and the relaxation of the surrounding crystal matrix are analysed. Point defects cause only local perturbations of atomic positions and charge-orbital order. After analysis of the supercell size effects for up to 448 atoms, we justify the use of small supercells with 56 atoms to make calculations for the cubic phase. The extensive experimental results of Dieckmann et al. on defects in magnetite at high temperature are deployed for comparison of our DFT+U results on Frenkel pair formation energies.

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Section: Discussionmentioning

confidence: 99%

Frenkel pair formation energy for cubic Fe₃O₄ in DFT + U calculations

Шутикова¹,

Stegaĭlov²

2022

J. Phys.: Condens. Matter

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“…Due to the strong relationship between the lattice, magnetic, and electronic degrees of freedom in most transition metal oxides, an external action (pumping) on one of the subsystems leads to significant changes and a response in the other. The details of calculations may be found in [9,13].…”

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confidence: 99%

Light-Induced Ultrafast Dynamics of Spin Crossovers under High Pressure

Orlov

Николаев

Nesterov

et al. 2021

J. Exp. Theor. Phys.

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Within the multielectron model of magnetic insulator with spin crossover under high pressure we have studied the mean field phase diagrams in pressure-temperature plane and dynamics of a sudden excited non equilibrium spin state. We obtain the different relaxation of the magnetization, high spin/low spin occupation numbers, and the metal-oxygen bond length for different values of the external pressure. We found the long living oscillations of magnetization without pressure and at small external pressure. Close to crossover pressure the smooth relaxation is accompanied with a set of sharp strongly non linear oscillations of magnetization and HS/LS occupation numbers that are accompanied by the Franck-Condon resonances.

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Photoinduced Nonlinear Dynamics of Strongly Correlated Systems with Spin Crossover: Autocatalytic Spin Transition

Orlov,

Nikolaev,

Paklin

2024

Jetp Lett.

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Nonlinear phenomena similar to the Belousov–Zhabotinsky reaction (autocatalytic oscillations of the population of high-spin and low-spin multielectron states of a transition metal ion) in open systems with spin crossover near bistability are considered. The conditions for possible experimental observation of autocatalytic oscillations of the magnetization in magnetically ordered systems with spin crossover are analyzed.

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Fluctuations of the Multiplicity of Co3+ Ions and Softening of the Phonon Spectrum of Rare-Earth Cobalt Oxides

Cited by 4 publications

References 21 publications

Frenkel pair formation energy for cubic Fe₃O₄ in DFT + U calculations

Frenkel pair formation energy for cubic Fe₃O₄ in DFT + U calculations

Light-Induced Ultrafast Dynamics of Spin Crossovers under High Pressure

Photoinduced Nonlinear Dynamics of Strongly Correlated Systems with Spin Crossover: Autocatalytic Spin Transition

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Fluctuations of the Multiplicity of Co3+ Ions and Softening of the Phonon Spectrum of Rare-Earth Cobalt Oxides

Cited by 4 publications

References 21 publications

Frenkel pair formation energy for cubic Fe3O4 in DFT + U calculations

Frenkel pair formation energy for cubic Fe3O4 in DFT + U calculations

Light-Induced Ultrafast Dynamics of Spin Crossovers under High Pressure

Photoinduced Nonlinear Dynamics of Strongly Correlated Systems with Spin Crossover: Autocatalytic Spin Transition

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Frenkel pair formation energy for cubic Fe₃O₄ in DFT + U calculations

Frenkel pair formation energy for cubic Fe₃O₄ in DFT + U calculations