Co K-edge XANES and spin-state transition of RCoO3 (R = La, Eu)

J. Y. Chang; B. N. Lin; Y. Y. Hsu; H. C. Ku

doi:10.1016/S0921-4526(02)02595-4

Co K-edge XANES and spin-state transition of RCoO₃ (R = La, Eu)

J. Y. Chang, B. N. Lin^*, Y. Y. Hsu, H. C. Ku

^*Corresponding author for this work

Research output: Contribution to journal › Article › peer-review

24 Citations (Scopus)

Abstract

Co K-edge X-ray absorption near-edge spectra at 300 K and magnetic studies for the rhombohedral LaCoO₃ with low-spin state to intermediate-spin (IS) state transition T_s≃105 K and orthorhombic EuCoO ₃ (T_s≃295 K) are reported. The small pre-edge feature observed is from 1s-3d dipole transition, which is weakly allowed through the hybridization of Co 4p states with 3d states of neighboring Co atoms. For both samples in the IS state, pre-edge can be fitted using three peaks with energy separation P₂ - P₁ = 2.0 eV for R = La and Eu, and P₃ - P₂ = 1.5 eV for R = La and 1.3 eV for R = Eu. Since the thermally excited IS state is a mixed t_2g ⁵e_g¹ and d⁷L (t_2g ⁶e_g¹ or t_2g⁵e _g²), with almost filled t_2g↑ states. From reported band structure calculation, the three peaks P₁, P ₂, P₃ are probably corresponding to the unfilled t _2g↓, e_g↑ and e_g↓ states, respectively.

Original language	English
Pages (from-to)	826-828
Number of pages	3
Journal	Physica B: Condensed Matter
Volume	329-333
Issue number	II
DOIs	https://doi.org/10.1016/S0921-4526(02)02595-4
Publication status	Published - 2003 May
Externally published	Yes

Keywords

Spin-state transition
XANES

ASJC Scopus subject areas

Electronic, Optical and Magnetic Materials
Condensed Matter Physics
Electrical and Electronic Engineering

Access to Document

10.1016/S0921-4526(02)02595-4

Cite this

@article{9cf4f79ce57d4069bbdc9ab273ccd7d9,

title = "Co K-edge XANES and spin-state transition of RCoO3 (R = La, Eu)",

abstract = "Co K-edge X-ray absorption near-edge spectra at 300 K and magnetic studies for the rhombohedral LaCoO3 with low-spin state to intermediate-spin (IS) state transition Ts≃105 K and orthorhombic EuCoO 3 (Ts≃295 K) are reported. The small pre-edge feature observed is from 1s-3d dipole transition, which is weakly allowed through the hybridization of Co 4p states with 3d states of neighboring Co atoms. For both samples in the IS state, pre-edge can be fitted using three peaks with energy separation P2 - P1 = 2.0 eV for R = La and Eu, and P3 - P2 = 1.5 eV for R = La and 1.3 eV for R = Eu. Since the thermally excited IS state is a mixed t2g 5eg1 and d7L (t2g 6eg1 or t2g5e g2), with almost filled t2g↑ states. From reported band structure calculation, the three peaks P1, P 2, P3 are probably corresponding to the unfilled t 2g↓, eg↑ and eg↓ states, respectively.",

keywords = "Spin-state transition, XANES",

author = "Chang, {J. Y.} and Lin, {B. N.} and Hsu, {Y. Y.} and Ku, {H. C.}",

note = "Funding Information: This work was supported by NSC of R.O.C. under contract Nos. NSC90-2112-M007-054 & -056. ",

year = "2003",

month = may,

doi = "10.1016/S0921-4526(02)02595-4",

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AU - Chang, J. Y.

AU - Lin, B. N.

AU - Hsu, Y. Y.

AU - Ku, H. C.

N1 - Funding Information: This work was supported by NSC of R.O.C. under contract Nos. NSC90-2112-M007-054 & -056.

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N2 - Co K-edge X-ray absorption near-edge spectra at 300 K and magnetic studies for the rhombohedral LaCoO3 with low-spin state to intermediate-spin (IS) state transition Ts≃105 K and orthorhombic EuCoO 3 (Ts≃295 K) are reported. The small pre-edge feature observed is from 1s-3d dipole transition, which is weakly allowed through the hybridization of Co 4p states with 3d states of neighboring Co atoms. For both samples in the IS state, pre-edge can be fitted using three peaks with energy separation P2 - P1 = 2.0 eV for R = La and Eu, and P3 - P2 = 1.5 eV for R = La and 1.3 eV for R = Eu. Since the thermally excited IS state is a mixed t2g 5eg1 and d7L (t2g 6eg1 or t2g5e g2), with almost filled t2g↑ states. From reported band structure calculation, the three peaks P1, P 2, P3 are probably corresponding to the unfilled t 2g↓, eg↑ and eg↓ states, respectively.

AB - Co K-edge X-ray absorption near-edge spectra at 300 K and magnetic studies for the rhombohedral LaCoO3 with low-spin state to intermediate-spin (IS) state transition Ts≃105 K and orthorhombic EuCoO 3 (Ts≃295 K) are reported. The small pre-edge feature observed is from 1s-3d dipole transition, which is weakly allowed through the hybridization of Co 4p states with 3d states of neighboring Co atoms. For both samples in the IS state, pre-edge can be fitted using three peaks with energy separation P2 - P1 = 2.0 eV for R = La and Eu, and P3 - P2 = 1.5 eV for R = La and 1.3 eV for R = Eu. Since the thermally excited IS state is a mixed t2g 5eg1 and d7L (t2g 6eg1 or t2g5e g2), with almost filled t2g↑ states. From reported band structure calculation, the three peaks P1, P 2, P3 are probably corresponding to the unfilled t 2g↓, eg↑ and eg↓ states, respectively.

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