Neutron-scattering-based evidence for interacting magnetic excitons in LaCo O3

S. El-Khatib, D. Phelan, J. G. Barker, H. Zheng, J. F. Mitchell, C. Leighton

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7 Scopus citations

Abstract

Recent progress with the thermally driven spin-state crossover in LaCoO3 has made it increasingly apparent that the nominally nonmagnetic low-spin ground state of this material actually hosts defect-based magnetism. This is investigated here via a small-angle neutron scattering (SANS) study of LaCoO3-δ crystals. The results provide (i) the surprising finding that the spin-state crossover is clearly reflected in SANS via quasieleastic and inelastic scattering from paramagnetic spin fluctuations and 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.

Original languageEnglish (US)
Article number060404
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume92
Issue number6
DOIs
StatePublished - Aug 6 2015

Bibliographical note

Publisher Copyright:
© 2015 American Physical Society. ©2015 American Physical Society.

How much support was provided by MRSEC?

  • Shared

Reporting period for MRSEC

  • Period 3

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