Phase Analysis of Magnetic Inclusions in Nanomaterials Based on Multiwall Carbon Nanotubes

K. Brzózkaa, M. Krajewski b, A. Małolepszy c, L. Stobińskic,d, T. Szumiata a, B. Górka a, M. Gawroński a and D. Wasik b aDepartment of Physics, Faculty of Mechanical Engineering, University of Technology and Humanities in Radom, J. Krasickiego 54, 26-600 Radom, Poland bFaculty of Physics, Institute of Experimental Physics, University of Warsaw, L. Pasteura 5, 02-093 Warsaw, Poland cFaculty of Chemical and Process Engineering, Warsaw University of Technology, L. Waryńskiego 1, 00-645 Warsaw, Poland dInstitute of Physical Chemistry, Polish Academy of Sciences, M. Kasprzaka 44/52, 01-224 Warsaw, Poland

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Functionalized multiwall carbon nanotubes as well as nanocomposite based on that material covered by nanoparticles composed of iron oxides were the subject of investigations. In order to identify all iron-bearing phases including those reported on the base of previous X-ray diffraction measurements, the transmission Mössbauer spectroscopy was utilized. The experiments were carried out both at room temperature and also at low temperatures. It was stated that in the investigated nanotubes some impurities were present, originating from the catalyst remains, in form: of Fe-C and α -Fe nanoparticles. The Mössbauer spectra collected for the nanocomposite showed a complex shape characteristic of temperature relaxations. The following subspectra related to iron-based phases were identified: sextet attributed to hematite, with hyperfine magnetic field reduced due to the temperature relaxations, sextet corresponding to iron carbide as well as two doublets linked to superparamagnetic hematite and ferrihydrites.

DOI: 10.12693/APhysPolA.131.863 PACS numbers: 61.05.Qr, 61.46.Fg, 61.48.De, 75.50.Tt, 75.75.Cd, 81.07.De