Magnetization Dynamics of an Individual Single‐Crystalline Fe‐Filled Carbon Nanotube

• Published in: Small (Weinheim an der Bergstrasse, Germany) Vol. 15; no. 49; pp. e1904315 - n/a
• Main Authors: Lenz, Kilian, Narkowicz, Ryszard, Wagner, Kai, Reiche, Christopher F., Körner, Julia, Schneider, Tobias, Kákay, Attila, Schultheiss, Helmut, Weissker, Uhland, Wolf, Daniel, Suter, Dieter, Büchner, Bernd, Fassbender, Jürgen, Mühl, Thomas, Lindner, Jürgen
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 01-12-2019
• Subjects: Brillouin light scattering; Carbon nanotubes; Chemical vapor deposition; Computer simulation; Crystal structure; Crystallinity; Damping; ferromagnetic nanotubes; Ferromagnetic resonance; Ferromagnetism; Iron; Light scattering; Magnetic measurement; Magnetization; micromagnetism; Nanotechnology; Nanowires; Organic chemistry; Resonance lines; Resonance scattering; Segments; Thin films; Transport; ferromagnetic nanotubes; carbon nanotubes; Brillouin light scattering; micromagnetism; ferromagnetic resonance
• ISSN: 1613-6810; 1613-6829
• DOI: 10.1002/smll.201904315

The magnetization dynamics of individual Fe‐filled multiwall carbon‐nanotubes (FeCNT), grown by chemical vapor deposition, are investigated by microresonator ferromagnetic resonance (FMR) and Brillouin light scattering (BLS) microscopy and corroborated by micromagnetic simulations. Currently, only static magnetometry measurements are available. They suggest that the FeCNTs consist of a single‐crystalline Fe nanowire throughout the length. The number and structure of the FMR lines and the abrupt decay of the spin‐wave transport seen in BLS indicate, however, that the Fe filling is not a single straight piece along the length. Therefore, a stepwise cutting procedure is applied in order to investigate the evolution of the ferromagnetic resonance lines as a function of the nanowire length. The results show that the FeCNT is indeed not homogeneous along the full length but is built from 300 to 400 nm long single‐crystalline segments. These segments consist of magnetically high quality Fe nanowires with almost the bulk values of Fe and with a similar small damping in relation to thin films, promoting FeCNTs as appealing candidates for spin‐wave transport in magnonic applications.
The magnetization dynamics of a single crystalline Fe‐filled multiwall carbon nanotube (FeCNT) are investigated by microresonator ferromagnetic resonance and Brillouin light scattering. Using a focused ion beam the initial FeCNT is successively shortened to obtain a single‐crystalline Fe wire. The cubic anisotropy and very narrow linewidth prove the high quality of the Fe nanowires.