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Abstract Adding Fe3O4nanoparticles to composites of [Fe(Htrz)2(trz)](BF4) spin-crossover polymer and polyaniline (PANI) drives a phase separation of both and restores the molecular structure and cooperative effects of the spin-crossover polymer without compromising the increased conductivity gained through the addition of PANI. We observe an increased on-off ratio for the DC conductivity owing to an enlarged off state resistivity and a 20 times larger AC conductivity of the on state compared with DC values. The Fe3O4nanoparticles, primarily confined to the [Fe(Htrz)2(trz)](BF4) phase, are ferromagnetically coupled to the local moment of the spin-crossover molecule suggesting the existence of an exchange interaction between both components.
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This content will become publicly available on December 12, 2025
Effect of different crystallographic properties on the electrical conductivity of two polymorphs of a spin crossover complex
Abstract In this study, the structure and transport properties of two polymorphs, nanoparticles and nanorods, of the iron(II) triazole [Fe(Htrz)2(trz)](BF4) spin crossover complex were compared. Conductive atomic force microscopy was used to map the electrical conductivity of individual nanoparticles and nanorods. The [Fe(Htrz)2(trz)](BF4) nanorods showed significantly higher conductivity compared to nanoparticles. This difference in electrical conductivity is partially associated to the different Fe–N bond lengths in each of the polymorphs, with an inverse relationship between Fe–N bond length and conductivity. Transport measurements were done on the nanorods for both high spin (at 380 K) and low spin (at 320 K) states under dark and illuminated conditions. The conductance is highest for the low spin state under dark conditions. In illumination, the conductance change is much diminished.
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- PAR ID:
- 10615140
- Publisher / Repository:
- Institute of Physics Publishing
- Date Published:
- Journal Name:
- Journal of Physics: Condensed Matter
- Volume:
- 37
- Issue:
- 8
- ISSN:
- 0953-8984
- Page Range / eLocation ID:
- 085302
- Subject(s) / Keyword(s):
- spin crossover complex, electrical conductivity, thermal hysteresis, nanoparticles, nanorods
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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