New-type phase transition coupled with spin and charge in iron mixed-valence system

Norimichi Kojima, Miho Itoi, Yuuki Ono, Masashi Ohkubo, Yasuhiro Kobayashi, Makoto Seto

Research output: Contribution to journalArticlepeer-review

Abstract

We have investigated the physical properties of (n-CnH 2n+1)4N [FeIIFeIII(dto) 3](dto = C2O2S2) by means of 57Fe Mössbauer spectroscopy, magnetic susceptibility, and ESR. From the analysis of 57Fe Mössbauer spectra and ESR signal, we have discovered a new type of first order phase transition around 120 K for (n-CnH2n+1)4N FeIIFe III(dto)3](n = 3, 4), where the charge transfer transition between FeII and Fe occurs reversibly. In the higher temperature phase, the FeIII (S = 1/2) and FeII (S = 2) sites are coordinated by six S atoms and six O atoms, respectively. In the lower temperature phase, on the other hand, the FeIII (S = 5/2) and Fe II(S = 0) sites are coordinated by six O atoms and six S atoms, respectively. Moreover, we have found the ferromagnetic phase transition in this system. The ferromagnetic order is induced by the charge transfer interaction between the FeIII (S = 5/2) and FeII (S = 0) sites.

Original languageEnglish
Pages (from-to)349-356
Number of pages8
JournalMolecular Crystals and Liquid Crystals Science and Technology Section A: Molecular Crystals and Liquid Crystals
Volume379
DOIs
Publication statusPublished - 2002
Externally publishedYes

Keywords

  • Charge transfer
  • Ferromagnetism
  • Mixed valence
  • Phase transition
  • Spin crossover

ASJC Scopus subject areas

  • Condensed Matter Physics

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