Evidence for the excited triplet of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msup><mml:mrow><mml:mi mathvariant="normal">Co</mml:mi></mml:mrow><mml:mrow><mml:mn>3</mml:mn><mml:mo>+</mml:mo></mml:mrow></mml:msup></mml:mrow></mml:math>in<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

Noguchi, S.; Kawamata, Shuichi; Okuda, K; Nojiri, Hiroyuki; Motokawa, M.

doi:10.1103/physrevb.66.094404

Cited by 204 publications

(197 citation statements)

References 28 publications

Supporting

Mentioning

168

Contrasting

Unclassified

Order By: Relevance

“…This state is clearly a HS state and should not be confused with an IS state. We find a g-factor of 3.2, in good agreement with the values found from ESR [32,34] and INS data [37].…”

supporting

confidence: 80%

See 1 more Smart Citation

Spin State Transition inLaCoO3Studied Using Soft X-ray Absorption Spectroscopy and Magnetic Circular Dichroism

et al. 2006

View full text Add to dashboard Cite

Using soft x-ray absorption spectroscopy and magnetic circular dichroism at the Co-L2,3 edge we reveal that the spin state transition in LaCoO3 can be well described by a low-spin ground state and a triply-degenerate high-spin first excited state. From the temperature dependence of the spectral lineshapes we find that LaCoO3 at finite temperatures is an inhomogeneous mixed-spinstate system. Crucial is that the magnetic circular dichroism signal in the paramagnetic state carries a large orbital momentum. This directly shows that the currently accepted low-/intermediate-spin picture is at variance. Parameters derived from these spectroscopies fully explain existing magnetic susceptibility, electron spin resonance and inelastic neutron data.PACS numbers: 71.28.+d, 71.70.Ch, 78.70.Dm LaCoO 3 shows a gradual non-magnetic to magnetic transition with temperature, which has been interpreted originally four decades ago as a gradual population of high spin (HS, t 4 2g e 2 g , S = 2) excited states starting from a low spin (LS, t 6 2g , S = 0) ground state [1,2,3,4,5,6,7,8]. This interpretation continued to be the starting point for experiments carried out up to roughly the first half of the 1990's [9,10,11,12]. All this changed with the theoretical work in 1996 by Korotin et al., who proposed on the basis of local density approximation + Hubbard U (LDA+U) band structure calculations, that the excited states are of the intermediate spin (IS, t 5 2g e 1 g , S = 1) type [13]. Since then many more studies have been carried out on LaCoO 3 with the majority of them [14,15,16,17,18,19,20,21,22,23,24,25,26,27] claiming to have proven the presence of this IS mechanism. In fact, this LDA+U work is so influential [28] that it forms the basis of most explanations for the fascinating properties of the recently synthesized layered cobaltate materials, which show giant magneto resistance as well as metal-insulator and ferroferri-antiferro-magnetic transitions with various forms of charge, orbital and spin ordering [29,30].In this paper we critically re-examine the spin state issue in LaCoO 3 . There has been several attempts made since 1996 in order to revive the LS-HS scenario [31,32,33,34,35], but these were overwhelmed by the above mentioned flurry of studies claiming the IS mechanism [14,15,16,17,18,19,20,21,22,23,24,25,26,27]. Moreover, a new investigation using inelastic neutron scattering (INS) has recently appeared in Phys. Rev. Lett.[36] making again the claim that the spin state transition involves the IS states. Here we used soft xray absorption spectroscopy (XAS) and magnetic circular dichroism (MCD) at the Co-L 2,3 edge and we revealed that the spin state transition in LaCoO 3 can be well described by a LS ground state and a triply degenerate HS excited state, and that an inhomogeneous mixed-spinstate system is formed. Parameters derived from these spectroscopies fully explain existing magnetic susceptibility and electron spin resonance (ESR) data, and provide support for an alternative interpretation of the INS [37]. C...

show abstract

“…This state is clearly a HS state and should not be confused with an IS state. We find a g-factor of 3.2, in good agreement with the values found from ESR [32,34] and INS data [37].…”

supporting

confidence: 80%

“…There has been several attempts made since 1996 in order to revive the LS-HS scenario [31,32,33,34,35], but these were overwhelmed by the above mentioned flurry of studies claiming the IS mechanism [14,15,16,17,18,19,20,21,22,23,24,25,26,27]. Moreover, a new investigation using inelastic neutron scattering (INS) has recently appeared in Phys.…”

mentioning

confidence: 99%

Spin State Transition inLaCoO3Studied Using Soft X-ray Absorption Spectroscopy and Magnetic Circular Dichroism

et al. 2006

View full text Add to dashboard Cite

show abstract

“…19 Here,l = 1 denotes the effective orbital momentum arising from the partial occupation of the t 2g orbital. However, this ESR result is in conflict with the susceptibility data, because the ESR data yield a g factor of about 3.5 which leads to a magnetic susceptibility that is about three times larger than that observed experimentally.…”

Section: 15mentioning

confidence: 99%

Spin-state transition and metal-insulator transition inLa1−xEuxCoO3

et al. 2005

View full text Add to dashboard Cite

We present a study of the structure, the electric resistivity, the magnetic susceptibility, and the thermal expansion of La1−xEuxCoO3. LaCoO3 shows a temperature-induced spin-state transition around 100 K and a metal-insulator transition around 500 K. Partial substitution of La 3+ by the smaller Eu 3+ causes chemical pressure and leads to a drastic increase of the spin gap from about 190 K in LaCoO3 to about 2000 K in EuCoO3, so that the spin-state transition is shifted to much higher temperatures. A combined analysis of thermal expansion and susceptibility gives evidence that the spin-state transition has to be attributed to a population of an intermediate-spin state without orbital degeneracy for x < 0.5 and with orbital degeneracy for larger x. In contrast to the spin-state transition, the metal-insulator transition is shifted only moderately to higher temperatures with increasing Eu content, showing that the metal-insulator transition occurs independently from the spin-state distribution of the Co 3+ ions. Around the metal-insulator transition the magnetic susceptibility shows a similar increase for all x and approaches a doping-independent value around 1000 K indicating that well above the metal-insulator transition the same spin state is approached for all x.

show abstract

“…We are convinced that the orbital degree of freedom (L) and the intraatomic spin-orbit coupling are indispensable for the physically adequate description of electronic and magnetic properties of LaMnO 3 . A discrete atomic-like electronic structure in the meV scale has been revealed recently in LaCoO 3 [16,17] confirming the basic assumption of the devel- …”

mentioning

confidence: 50%

Ground state, electronic structure and magnetism of LaMnO3

Radwański

Ropka²

2004

Journal of Magnetism and Magnetic Materials

View full text Add to dashboard Cite

We have calculated the discrete low-energy electronic structure in LaMnO 3 originating from the atomic-like states of the strongly correlated 3d 4 electronic system occurring in the Mn 3+ ion. We take into account very strong intra-atomic correlations, crystal field interactions and the intra-atomic spin-orbit coupling. We calculated magnetic and paramagnetic state of LaMnO 3 within the consistent description given by Quantum Atomistic Solid State Theory (QUASST). Our studies indicate that the intra-atomic spin-orbit coupling and the orbital magnetism are indispensable for the physically adequate description of electronic and magnetic properties of LaMnO 3 .

show abstract

Evidence for the excited triplet ofCo3+inLaCoO3

Cited by 204 publications

References 28 publications

Spin State Transition inLaCoO3Studied Using Soft X-ray Absorption Spectroscopy and Magnetic Circular Dichroism

Spin State Transition inLaCoO3Studied Using Soft X-ray Absorption Spectroscopy and Magnetic Circular Dichroism

Spin-state transition and metal-insulator transition inLa1−xEuxCoO3

Ground state, electronic structure and magnetism of LaMnO3

Contact Info

Product

Resources

About