Temperature dependences of paramagnetic response in oxidized spark plasma sintered carbon nanotubes: The way of understanding the local electronic structure

• Published in: Solid state sciences 2022-10, Vol.132, p.106996, Article 106996
• Main Authors: Savilov, Serguei V., Ulyanov, Alexander N., Desyatov, Andrey V., Suslova, Evgeniya V.
• Format: Article
• Language: English
• Subjects: Carbon nanotubes; Curie-weiss law; Electron paramagnetic resonance; Paramagnetic matrix; Superparamagnetic inclusions
• ISSN: 1293-2558; 1873-3085
• DOI: 10.1016/j.solidstatesciences.2022.106996

Electron paramagnetic resonance (EPR) spectroscopy was used to study an electronic structure of carbon nanotubes (CNTs) consolidated by spark plasma sintering and additionally oxidized in vapor of boiling nitric acid. Two components were distinguished in the EPR absorption spectra: narrow and broad lines with different g-factors. This testified to the different surrounding of paramagnetic centers associated with the lines. Temperature dependence of spin numbers, associated with the narrow line, transfers from Curie-Weiss law to Curie law with increasing temperature. EPR susceptibility, associated with the broad line, can be attributed to a paramagnetic matrix with superparamagnetic inclusions. [Display omitted] •Consolidated oxidized carbon nanotubes are studied by electron paramagnetic resonance.•Two components of paramagnetic response were distinguished in absorption spectra.•Dependence of susceptibility (χ) associated with both line changes with temperature.•χ associated with narrow line transfer from Curie-Weiss to Curie law with temperature.•Superparamagnetic inclusions in paramagnetic matrix were observed.