Evidence for magnetic polarons in hole-doped cobalt perovskites

A. Podlesnyak; A. Furrer; Th Strässle; E. Pomjakushina; K. Conder; D. I. Khomskii

doi:10.1557/proc-1256-n04-02

Evidence for magnetic polarons in hole-doped cobalt perovskites

A. Podlesnyak, A. Furrer, Th Strässle, E. Pomjakushina, K. Conder, D. I. Khomskii

Direct Geometry

Research output: Chapter in Book/Report/Conference proceeding › Conference contribution › peer-review

Abstract

A substitution of La³⁺ by Sr²⁺ in LaCoO₃ induces holes in the low-spin ground state of the Co ions, which behave like magnetic impurities with a very high spin value (13 μ_B per hole). In this work, using single-crystal neutron spectroscopy, we prove that the charges introduced by strontium doping do not remain localized at the cobalt sites. Instead, each hole not only creates Co⁴⁺ in low-spin state, but it also transforms the six nearest neighboring Co³⁺ ions to the intermediate-spin state thereby forming a magnetic seven-site (heptamer) polaron. Spin-state polarons behave like magnetic nanoparticles embedded in an insulating nonmagnetic matrix. Therefore, lightly doped La_1-xSr _xCoO₃ is a natural analog to artificial structures composed of ferromagnetic particles in insulating matrices.

Original language	English
Title of host publication	Functional Oxide Nanostructures and Heterostructures
Publisher	Materials Research Society
Pages	23-28
Number of pages	6
ISBN (Print)	9781617822209
DOIs	https://doi.org/10.1557/proc-1256-n04-02
State	Published - 2010

Publication series

Name	Materials Research Society Symposium Proceedings
Volume	1256
ISSN (Print)	0272-9172

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10.1557/proc-1256-n04-02

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title = "Evidence for magnetic polarons in hole-doped cobalt perovskites",

abstract = "A substitution of La3+ by Sr2+ in LaCoO3 induces holes in the low-spin ground state of the Co ions, which behave like magnetic impurities with a very high spin value (13 μB per hole). In this work, using single-crystal neutron spectroscopy, we prove that the charges introduced by strontium doping do not remain localized at the cobalt sites. Instead, each hole not only creates Co4+ in low-spin state, but it also transforms the six nearest neighboring Co3+ ions to the intermediate-spin state thereby forming a magnetic seven-site (heptamer) polaron. Spin-state polarons behave like magnetic nanoparticles embedded in an insulating nonmagnetic matrix. Therefore, lightly doped La1-xSr xCoO3 is a natural analog to artificial structures composed of ferromagnetic particles in insulating matrices.",

author = "A. Podlesnyak and A. Furrer and Th Str{\"a}ssle and E. Pomjakushina and K. Conder and Khomskii, {D. I.}",

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doi = "10.1557/proc-1256-n04-02",

language = "English",

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Evidence for magnetic polarons in hole-doped cobalt perovskites. / Podlesnyak, A.; Furrer, A.; Strässle, Th et al.
Functional Oxide Nanostructures and Heterostructures. Materials Research Society, 2010. p. 23-28 (Materials Research Society Symposium Proceedings; Vol. 1256).

Research output: Chapter in Book/Report/Conference proceeding › Conference contribution › peer-review

TY - GEN

T1 - Evidence for magnetic polarons in hole-doped cobalt perovskites

AU - Podlesnyak, A.

AU - Furrer, A.

AU - Strässle, Th

AU - Pomjakushina, E.

AU - Conder, K.

AU - Khomskii, D. I.

PY - 2010

Y1 - 2010

N2 - A substitution of La3+ by Sr2+ in LaCoO3 induces holes in the low-spin ground state of the Co ions, which behave like magnetic impurities with a very high spin value (13 μB per hole). In this work, using single-crystal neutron spectroscopy, we prove that the charges introduced by strontium doping do not remain localized at the cobalt sites. Instead, each hole not only creates Co4+ in low-spin state, but it also transforms the six nearest neighboring Co3+ ions to the intermediate-spin state thereby forming a magnetic seven-site (heptamer) polaron. Spin-state polarons behave like magnetic nanoparticles embedded in an insulating nonmagnetic matrix. Therefore, lightly doped La1-xSr xCoO3 is a natural analog to artificial structures composed of ferromagnetic particles in insulating matrices.

AB - A substitution of La3+ by Sr2+ in LaCoO3 induces holes in the low-spin ground state of the Co ions, which behave like magnetic impurities with a very high spin value (13 μB per hole). In this work, using single-crystal neutron spectroscopy, we prove that the charges introduced by strontium doping do not remain localized at the cobalt sites. Instead, each hole not only creates Co4+ in low-spin state, but it also transforms the six nearest neighboring Co3+ ions to the intermediate-spin state thereby forming a magnetic seven-site (heptamer) polaron. Spin-state polarons behave like magnetic nanoparticles embedded in an insulating nonmagnetic matrix. Therefore, lightly doped La1-xSr xCoO3 is a natural analog to artificial structures composed of ferromagnetic particles in insulating matrices.

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BT - Functional Oxide Nanostructures and Heterostructures

PB - Materials Research Society

ER -

Evidence for magnetic polarons in hole-doped cobalt perovskites

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