High-pressure p-p band closure of the negative-delta sign Sr2FeO4 perovskite

M. P. Pasternak*, M. Amanowicz, A. P. Milner, G. Kh Rozenberg, R. D. Taylor, G. R. Hearne, K. E. Brister

*Corresponding author for this work

Research output: Contribution to journalArticle

Abstract

Recent analyses of X-ray photoemission (XPS) spectroscopy performed in some high-valence transition metal (TM) oxide insulators have implied the existence of band gaps of the p-p type, corresponding to dnL + dnL → dn + dnL2 charge fluctuations. This band gap is neither the d-d Mott-Hubbard nor the p-d charge-transfer type common to many insulating TM compounds. Thus, it is expected that upon metallization the magnetic moments and ordering will be barely affected since the d-bands are not directly involved in the band-gap closure. We have investigated high-pressure magnetic, structural, and transport properties of Sr2FeO4 (Fe4+), an antiferromagnetic (TN = 60 K) insulator, using diamond anvil cells up to P = 30 GPa. With the increasing pressure a significant increase in the conductance (σ) is observed and at PM = 19 GPa the compound metallizes as concluded from the onset of a negative slope of σ(T). Magnetic studies performed with 57Fe Mössbauer spectroscopy showed no evidence of a magnetic moment collapse at PM and beyond, up to P = 30 GPa. No structural phase transition occurs up to 30 GPa. The coexistence of magnetic moments and metallic state in this oxide is clear evidence of an intra-ligand p-p gap as proposed by the XPS data analyses.

Original languageEnglish (US)
Pages (from-to)1377-1378
Number of pages2
JournalJournal of Magnetism and Magnetic Materials
Volume177-181
Issue numberPART 2
DOIs
StatePublished - Jan 1998

Keywords

  • High pressure
  • Mössbauer spectroscopy
  • Phase transitions - metal-insulator
  • X-ray diffraction

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

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    Pasternak, M. P., Amanowicz, M., Milner, A. P., Rozenberg, G. K., Taylor, R. D., Hearne, G. R., & Brister, K. E. (1998). High-pressure p-p band closure of the negative-delta sign Sr2FeO4 perovskite. Journal of Magnetism and Magnetic Materials, 177-181(PART 2), 1377-1378. https://doi.org/10.1016/S0304-8853(97)00610-0