Comparison of the electronic structure of LnBaCo2O 5+δ (Ln = Gd, Dy; Ln-112) and LnBaCo4O7 (Ln = Yb; Ln-114) single-crystal surfaces using resonant photoemission

H. M. Rafique; W. R. Flavell; A. G. Thomas; K. L. Syres; S. N. Barilo; S. V. Shiryaev; G. L. Bychkov; D. M P Holland; A. E R Malins; G. Miller; V. R. Dhanak

doi:10.1016/j.elspec.2010.12.012

Comparison of the electronic structure of LnBaCo2O 5+δ (Ln = Gd, Dy; Ln-112) and LnBaCo4O7 (Ln = Yb; Ln-114) single-crystal surfaces using resonant photoemission

H. M. Rafique, W. R. Flavell, A. G. Thomas, K. L. Syres, S. N. Barilo, S. V. Shiryaev, G. L. Bychkov, D. M P Holland, A. E R Malins, G. Miller, V. R. Dhanak

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Abstract

A comparison of the electronic structure of LnBaCo2O 5+( (Ln = Gd, Dy; Ln-112) and LnBaCo4O7+δ (Ln = Yb; Ln-114) single-crystal surfaces has been made using synchrotron photoemission spectroscopy. Resonant photoemission is used to identify the atomic parentage of the valence band states of Ln-114. The states close to the Fermi energy are found to be of mixed Co 3d/O 2p character. Comparison of the photoemission results for the two systems allows unambiguous identification of the spectral signal due to low spin octahedral Co3+ in Ln-112. High resolution valence band spectra taken as a function of temperature reveal the presence of the metal-insulator (MI) transition in Ln-112 in the 300-400 K temperature range. The gradual changes in the spectral profile of the low energy states with temperature rule out a sudden 'high spin-low spin' switch as the mechanism of the MI transition. They are instead consistent with a gradually shifting equilibrium between three states - low spin, intermediate spin and high spin. © 2010 Elsevier B.V. All rights reserved.

Original language	English
Pages (from-to)	227-231
Number of pages	4
Journal	Journal of Electron Spectroscopy and Related Phenomena
Volume	184
Issue number	3-6
DOIs	https://doi.org/10.1016/j.elspec.2010.12.012
Publication status	Published - Apr 2011

Keywords

Cobalt oxide
Dy
Ln-112)
Ln-114)
LnBaCo2O5+( (Ln = Gd
LnBaCo4O7 (Ln = Yb
Metal-insulator transition
Resonant photoemission

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Rafique, H. M., Flavell, W. R., Thomas, A. G., Syres, K. L., Barilo, S. N., Shiryaev, S. V., Bychkov, G. L., Holland, D. M. P., Malins, A. E. R., Miller, G., & Dhanak, V. R. (2011). Comparison of the electronic structure of LnBaCo2O 5+δ (Ln = Gd, Dy; Ln-112) and LnBaCo4O7 (Ln = Yb; Ln-114) single-crystal surfaces using resonant photoemission. Journal of Electron Spectroscopy and Related Phenomena, 184(3-6), 227-231. https://doi.org/10.1016/j.elspec.2010.12.012

@article{ee89207aa0ba47a0a3109fce815c9447,

title = "Comparison of the electronic structure of LnBaCo2O 5+δ (Ln = Gd, Dy; Ln-112) and LnBaCo4O7 (Ln = Yb; Ln-114) single-crystal surfaces using resonant photoemission",

abstract = "A comparison of the electronic structure of LnBaCo2O 5+( (Ln = Gd, Dy; Ln-112) and LnBaCo4O7+δ (Ln = Yb; Ln-114) single-crystal surfaces has been made using synchrotron photoemission spectroscopy. Resonant photoemission is used to identify the atomic parentage of the valence band states of Ln-114. The states close to the Fermi energy are found to be of mixed Co 3d/O 2p character. Comparison of the photoemission results for the two systems allows unambiguous identification of the spectral signal due to low spin octahedral Co3+ in Ln-112. High resolution valence band spectra taken as a function of temperature reveal the presence of the metal-insulator (MI) transition in Ln-112 in the 300-400 K temperature range. The gradual changes in the spectral profile of the low energy states with temperature rule out a sudden 'high spin-low spin' switch as the mechanism of the MI transition. They are instead consistent with a gradually shifting equilibrium between three states - low spin, intermediate spin and high spin. {\textcopyright} 2010 Elsevier B.V. All rights reserved.",

keywords = "Cobalt oxide, Dy, Ln-112), Ln-114), LnBaCo2O5+( (Ln = Gd, LnBaCo4O7 (Ln = Yb, Metal-insulator transition, Resonant photoemission",

author = "Rafique, {H. M.} and Flavell, {W. R.} and Thomas, {A. G.} and Syres, {K. L.} and Barilo, {S. N.} and Shiryaev, {S. V.} and Bychkov, {G. L.} and Holland, {D. M P} and Malins, {A. E R} and G. Miller and Dhanak, {V. R.}",

year = "2011",

month = apr,

doi = "10.1016/j.elspec.2010.12.012",

language = "English",

volume = "184",

pages = "227--231",

journal = "Journal of Electron Spectroscopy and Related Phenomena",

publisher = "Elsevier BV",

number = "3-6",

}

Rafique, HM, Flavell, WR , Thomas, AG, Syres, KL, Barilo, SN, Shiryaev, SV, Bychkov, GL, Holland, DMP, Malins, AER, Miller, G & Dhanak, VR 2011, 'Comparison of the electronic structure of LnBaCo2O 5+δ (Ln = Gd, Dy; Ln-112) and LnBaCo4O7 (Ln = Yb; Ln-114) single-crystal surfaces using resonant photoemission', Journal of Electron Spectroscopy and Related Phenomena, vol. 184, no. 3-6, pp. 227-231. https://doi.org/10.1016/j.elspec.2010.12.012

Comparison of the electronic structure of LnBaCo2O 5+δ (Ln = Gd, Dy; Ln-112) and LnBaCo4O7 (Ln = Yb; Ln-114) single-crystal surfaces using resonant photoemission. / Rafique, H. M.; Flavell, W. R.; Thomas, A. G. et al.
In: Journal of Electron Spectroscopy and Related Phenomena, Vol. 184, No. 3-6, 04.2011, p. 227-231.

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

TY - JOUR

T1 - Comparison of the electronic structure of LnBaCo2O 5+δ (Ln = Gd, Dy; Ln-112) and LnBaCo4O7 (Ln = Yb; Ln-114) single-crystal surfaces using resonant photoemission

AU - Rafique, H. M.

AU - Flavell, W. R.

AU - Thomas, A. G.

AU - Syres, K. L.

AU - Barilo, S. N.

AU - Shiryaev, S. V.

AU - Bychkov, G. L.

AU - Holland, D. M P

AU - Malins, A. E R

AU - Miller, G.

AU - Dhanak, V. R.

PY - 2011/4

Y1 - 2011/4

N2 - A comparison of the electronic structure of LnBaCo2O 5+( (Ln = Gd, Dy; Ln-112) and LnBaCo4O7+δ (Ln = Yb; Ln-114) single-crystal surfaces has been made using synchrotron photoemission spectroscopy. Resonant photoemission is used to identify the atomic parentage of the valence band states of Ln-114. The states close to the Fermi energy are found to be of mixed Co 3d/O 2p character. Comparison of the photoemission results for the two systems allows unambiguous identification of the spectral signal due to low spin octahedral Co3+ in Ln-112. High resolution valence band spectra taken as a function of temperature reveal the presence of the metal-insulator (MI) transition in Ln-112 in the 300-400 K temperature range. The gradual changes in the spectral profile of the low energy states with temperature rule out a sudden 'high spin-low spin' switch as the mechanism of the MI transition. They are instead consistent with a gradually shifting equilibrium between three states - low spin, intermediate spin and high spin. © 2010 Elsevier B.V. All rights reserved.

AB - A comparison of the electronic structure of LnBaCo2O 5+( (Ln = Gd, Dy; Ln-112) and LnBaCo4O7+δ (Ln = Yb; Ln-114) single-crystal surfaces has been made using synchrotron photoemission spectroscopy. Resonant photoemission is used to identify the atomic parentage of the valence band states of Ln-114. The states close to the Fermi energy are found to be of mixed Co 3d/O 2p character. Comparison of the photoemission results for the two systems allows unambiguous identification of the spectral signal due to low spin octahedral Co3+ in Ln-112. High resolution valence band spectra taken as a function of temperature reveal the presence of the metal-insulator (MI) transition in Ln-112 in the 300-400 K temperature range. The gradual changes in the spectral profile of the low energy states with temperature rule out a sudden 'high spin-low spin' switch as the mechanism of the MI transition. They are instead consistent with a gradually shifting equilibrium between three states - low spin, intermediate spin and high spin. © 2010 Elsevier B.V. All rights reserved.

KW - Cobalt oxide

KW - Dy

KW - Ln-112)

KW - Ln-114)

KW - LnBaCo2O5+( (Ln = Gd

KW - LnBaCo4O7 (Ln = Yb

KW - Metal-insulator transition

KW - Resonant photoemission

U2 - 10.1016/j.elspec.2010.12.012

DO - 10.1016/j.elspec.2010.12.012

M3 - Article

VL - 184

SP - 227

EP - 231

JO - Journal of Electron Spectroscopy and Related Phenomena

JF - Journal of Electron Spectroscopy and Related Phenomena

IS - 3-6

ER -

Comparison of the electronic structure of LnBaCo2O 5+δ (Ln = Gd, Dy; Ln-112) and LnBaCo4O7 (Ln = Yb; Ln-114) single-crystal surfaces using resonant photoemission

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