Low temperature Schottky anomalies in the specific heat of LaCoO 3: Defect-stabilized finite spin states

C. He; H. Zheng; J. F. Mitchell; M. L. Foo; R. J. Cava; C. Leighton

doi:10.1063/1.3098374

Low temperature Schottky anomalies in the specific heat of LaCoO ₃: Defect-stabilized finite spin states

C. He, H. Zheng, J. F. Mitchell, M. L. Foo, R. J. Cava, C. Leighton

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49 Scopus citations

Abstract

Measurement of the low temperature specific heat of LaCoO₃ single crystals reveals a previously unobserved Schottky anomaly with an energy level splitting, 0.5 meV, that is associated with the first excited spin state of the Co³⁺ ion. These states persist well below 2 K and have a g -factor around 3.5, consistent with the high-spin spin-orbit triplet, implying the existence of a low density (approximately 0.1% of the sites) of finite-spin Co ions even in the T=0 limit. We propose that these states are trapped at defects and are consistent with the magnetic excitons observed in earlier work.

Original language	English (US)
Article number	102514
Journal	Applied Physics Letters
Volume	94
Issue number	10
DOIs	https://doi.org/10.1063/1.3098374
State	Published - 2009

All Science Journal Classification (ASJC) codes

Physics and Astronomy (miscellaneous)

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10.1063/1.3098374

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title = "Low temperature Schottky anomalies in the specific heat of LaCoO 3: Defect-stabilized finite spin states",

abstract = "Measurement of the low temperature specific heat of LaCoO3 single crystals reveals a previously unobserved Schottky anomaly with an energy level splitting, 0.5 meV, that is associated with the first excited spin state of the Co3+ ion. These states persist well below 2 K and have a g -factor around 3.5, consistent with the high-spin spin-orbit triplet, implying the existence of a low density (approximately 0.1% of the sites) of finite-spin Co ions even in the T=0 limit. We propose that these states are trapped at defects and are consistent with the magnetic excitons observed in earlier work.",

author = "C. He and H. Zheng and Mitchell, {J. F.} and Foo, {M. L.} and Cava, {R. J.} and C. Leighton",

note = "Funding Information: Work supported primarily by DoE (Grant No. DE-FG02-06ER46275) with additional support from NSF (Grant No. DMR-0804432 and DMR02-13706). ANL is supported by DoE under Grant No. DE-AC02-06CH11357.",

year = "2009",

doi = "10.1063/1.3098374",

language = "English (US)",

volume = "94",

journal = "Applied Physics Letters",

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publisher = "American Institute of Physics",

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T1 - Low temperature Schottky anomalies in the specific heat of LaCoO 3

T2 - Defect-stabilized finite spin states

AU - He, C.

AU - Zheng, H.

AU - Mitchell, J. F.

AU - Foo, M. L.

AU - Cava, R. J.

AU - Leighton, C.

N1 - Funding Information: Work supported primarily by DoE (Grant No. DE-FG02-06ER46275) with additional support from NSF (Grant No. DMR-0804432 and DMR02-13706). ANL is supported by DoE under Grant No. DE-AC02-06CH11357.

PY - 2009

Y1 - 2009

N2 - Measurement of the low temperature specific heat of LaCoO3 single crystals reveals a previously unobserved Schottky anomaly with an energy level splitting, 0.5 meV, that is associated with the first excited spin state of the Co3+ ion. These states persist well below 2 K and have a g -factor around 3.5, consistent with the high-spin spin-orbit triplet, implying the existence of a low density (approximately 0.1% of the sites) of finite-spin Co ions even in the T=0 limit. We propose that these states are trapped at defects and are consistent with the magnetic excitons observed in earlier work.

AB - Measurement of the low temperature specific heat of LaCoO3 single crystals reveals a previously unobserved Schottky anomaly with an energy level splitting, 0.5 meV, that is associated with the first excited spin state of the Co3+ ion. These states persist well below 2 K and have a g -factor around 3.5, consistent with the high-spin spin-orbit triplet, implying the existence of a low density (approximately 0.1% of the sites) of finite-spin Co ions even in the T=0 limit. We propose that these states are trapped at defects and are consistent with the magnetic excitons observed in earlier work.

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Low temperature Schottky anomalies in the specific heat of LaCoO ₃: Defect-stabilized finite spin states

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