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Title: Neutron-scattering-based evidence for interacting magnetic excitons in LaCo O 3

Abstract

Recent progress with the thermally-driven spin-state crossover in LaCoO3 has made it increasingly apparent that the nominally non-magnetic low spin ground state of this material actually hosts novel defect-'based magnetism. This is investigated here via a small-angle neutron scattering (SANS) study of LaCoO3-s crystals. The results provide: (i) the surprising finding that the spin-state crossover is clearly reflected in SANS via quasielastic/inelastic scattering from paramagnetic spin fluctuations/excitations, and (ii) evidence for the formation, likely around oxygen defects, of local entities known as magnetic excitons. The latter generate distinct magnetic scattering below 60 K, providing valuable quantitative information on exciton densities and interactions. Potential relevance to the unexpected ferromagnetism recently discovered in epitaxial LaCoO3 films is discussed.

Authors:
; ; ; ; ;
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES)
OSTI Identifier:
1356990
DOE Contract Number:  
AC02-06CH11357
Resource Type:
Journal Article
Journal Name:
Physical Review. B, Condensed Matter and Materials Physics
Additional Journal Information:
Journal Volume: 92; Journal Issue: 6; Journal ID: ISSN 1098-0121
Publisher:
American Physical Society (APS)
Country of Publication:
United States
Language:
English

Citation Formats

El-Khatib, S., Phelan, D., Barker, J. G., Zheng, H., Mitchell, J. F., and Leighton, C. Neutron-scattering-based evidence for interacting magnetic excitons in LaCoO3. United States: N. p., 2015. Web. doi:10.1103/PhysRevB.92.060404.
El-Khatib, S., Phelan, D., Barker, J. G., Zheng, H., Mitchell, J. F., & Leighton, C. Neutron-scattering-based evidence for interacting magnetic excitons in LaCoO3. United States. https://doi.org/10.1103/PhysRevB.92.060404
El-Khatib, S., Phelan, D., Barker, J. G., Zheng, H., Mitchell, J. F., and Leighton, C. 2015. "Neutron-scattering-based evidence for interacting magnetic excitons in LaCoO3". United States. https://doi.org/10.1103/PhysRevB.92.060404.
@article{osti_1356990,
title = {Neutron-scattering-based evidence for interacting magnetic excitons in LaCoO3},
author = {El-Khatib, S. and Phelan, D. and Barker, J. G. and Zheng, H. and Mitchell, J. F. and Leighton, C.},
abstractNote = {Recent progress with the thermally-driven spin-state crossover in LaCoO3 has made it increasingly apparent that the nominally non-magnetic low spin ground state of this material actually hosts novel defect-'based magnetism. This is investigated here via a small-angle neutron scattering (SANS) study of LaCoO3-s crystals. The results provide: (i) the surprising finding that the spin-state crossover is clearly reflected in SANS via quasielastic/inelastic scattering from paramagnetic spin fluctuations/excitations, and (ii) evidence for the formation, likely around oxygen defects, of local entities known as magnetic excitons. The latter generate distinct magnetic scattering below 60 K, providing valuable quantitative information on exciton densities and interactions. Potential relevance to the unexpected ferromagnetism recently discovered in epitaxial LaCoO3 films is discussed.},
doi = {10.1103/PhysRevB.92.060404},
url = {https://www.osti.gov/biblio/1356990}, journal = {Physical Review. B, Condensed Matter and Materials Physics},
issn = {1098-0121},
number = 6,
volume = 92,
place = {United States},
year = {Sat Aug 01 00:00:00 EDT 2015},
month = {Sat Aug 01 00:00:00 EDT 2015}
}