Competition of various spin states of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">LaCoO</mml:mi></mml:mrow><mml:mrow><mml:mn>3</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>

Zhuang, Min; Zhang, Weiyi; Ming, Nai‐Ben

doi:10.1103/physrevb.57.10705

Cited by 80 publications

(59 citation statements)

References 21 publications

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“…In the ground state (T = 0 K), LaCoO 3 is a diamagnetic insulator with a low-spin (S=0, t 16 The nature of this spin-state transition is still under debate: inelastic neutron scattering, 17 x-ray absorption spectroscopy (XAS) and magnetic circular dichroism experiments 18 suggest a first-order transition to the high-spin (HS) state, while other x-ray photoemission (XPS) and XAS spectra in addition to electron energy loss (EELS) spectroscopy suggest the intermediate-spin (IS) state. 12,19,20,21 Similarly, Hartree-Fock cluster 22 and full-potential DFT calculations 15 suggest the HS state is more stable than the IS state, while other LSDA + U calculations obtain the reverse result.…”

Section: Introductionmentioning

confidence: 99%

Structural effects on the spin-state transition in epitaxially strainedLaCoO3films

Rondinelli

Spaldin

2009

Phys. Rev. B

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Using density functional theory within the LSDA + U method, we investigate the effect of strain on the spin state and magnetic ordering in perovskite lanthanum cobaltite, LaCoO3. We show that, while strain-induced changes in lattice parameters are insufficient to stabilize a non-zero spin state, additional heteroepitaxial symmetry constraints -in particular the suppression of octahedral rotations -stabilize a ferromagnetic intermediate-spin state. By comparing with experimental data for the bulk material, we calculate an upper bound on the Hubbard U value, and describe the role that the on-site Coulomb interaction plays in determining the spin-state configuration.

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Section: Introductionmentioning

confidence: 99%

Structural effects on the spin-state transition in epitaxially strainedLaCoO3films

Rondinelli

Spaldin

2009

Phys. Rev. B

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“…The 3d orbitals of the Co 3+ ion, surrounded with octahedrally coordinated O 2− ions, are split into the t 2g (triply degenerate) and the e g (doubly degenerate) orbitals in the lower and upper energy levels, respectively. The low temperature ground state is nonmagnetic (S=0) insulating nature with Co 3+ ions being in the low spin (LS) state configuration (3d 6 ; t 6 2g e 0 g ) [17]. However, with increasing temperature, the magnetic susceptibility (χ) shows two prominent features/transitions at around 90 K and 500 K [18][19][20].…”

Section: Introductionmentioning

confidence: 99%

Anomalous magnetic and spin glass behavior in Nb-substituted LaCo1−xNbxO3

Shukla

Dhaka

2018

Phys. Rev. B

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We report the structural, magnetic, transport and electronic properties of Nb substituted LaCo1−xNbxO3 (x = 0-0.2). The Rietveld analysis of x-ray diffraction data demonstrate structural phase transitions from rhombohedral to orthorhombic and further to monoclinic with increasing the Nb concentration up to x ≥ 0.2. Interestingly, we observed dramatic changes in the magnetization (M) with increasing the Nb concentration, as the M sharply increases below 10 K even at 2.5% substitution. Furthermore, ac susceptibility data show the spin-glass behavior in x = 0.1 sample. We find that the density of states near the Fermi level decreases and the activation energy increases, which results in the decreasing conductivity with higher Nb concentration. A significant shift in the peak position of A2g phonon mode has been observed using Raman spectroscopy, which indicates the change in the coupling due to the structural distortion with Nb substitution. The core-level photoemission study confirms that the Nb is present in 5+ valence state. Our study reveals that the nonmagnetic Nb 5+ (d 0 ) substitution converts Co 3+ ions to Co 2+ and stabilize both in the high-spin state. Our results suggest that structural and spin-state transitions as well as the difference in the ionic radii between Nb 5+ and Co 3+ are playing an important role in tuning the physical properties.

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“…In passing, we would like to emphasize that even though the occupancy histograms show that LaCoO 3 is in a mixed spin state, this is a spatially homogenous mixed state (such as those discussed in references [19,51]) and not an inhomogeneous spin state, such as those discussed in various theoretical studies 44,[52][53][54] and also discussed in relation to the Magnetic Circular Dichroism results in Ref. [9].…”

Section: The Spin State Transitionmentioning

confidence: 99%

Role of entropy and structural parameters in the spin-state transition of LaCoO3

Chakrabarti¹,

Birol²,

Haule³

2017

Phys. Rev. Materials

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The spin state transition in LaCoO3 has eluded description for decades despite concerted theoretical and experimental effort. In this study, we approach this problem using fully charge self-consistent Density Functional Theory + Embedded Dynamical Mean Field Theory (DFT+DMFT). We show from first principles that LaCoO3 cannot be described by a single, pure spin state at any temperature. Instead, we observe a gradual change in the population of higher spin multiplets with increasing temperature, with the high spin multiplets being excited at the onset of the spin state transition followed by the intermediate spin multiplets being excited at the metal insulator transition temperature. We explicitly elucidate the critical role of lattice expansion and oxygen octahedral rotations in the spin state transition. We also reproduce, from first principles, that the spin state transition and the metal-insulator transition in LaCoO3 occur at different temperature scales. In addition, our results shed light on the importance of electronic entropy in driving the spin state transition, which has so far been ignored in all first principles studies of this material.

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Competition of various spin states ofLaCoO3

Cited by 80 publications

References 21 publications

Structural effects on the spin-state transition in epitaxially strainedLaCoO3films

Structural effects on the spin-state transition in epitaxially strainedLaCoO3films

Anomalous magnetic and spin glass behavior in Nb-substituted LaCo1−xNbxO3

Role of entropy and structural parameters in the spin-state transition of LaCoO3

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