Magnetic fullerenes inside single-wall carbon nanotubes

TL;DR

This study demonstrates the formation of magnetic C59N fullerenes inside single-wall carbon nanotubes, revealing their magnetic behavior, charge transfer properties, and interactions with the nanotube conduction electrons.

Contribution

It introduces a method to synthesize magnetic fullerenes inside nanotubes and characterizes their magnetic and electronic interactions with the host.

Findings

C59N fullerenes exhibit hindered, anisotropic rotation inside nanotubes.

Reversible charge transfer occurs above 350 K, affecting spin relaxation.

C60 co-encapsulation leads to heterodimer formation with distinct relaxation behavior.

Abstract

C59N magnetic fullerenes were formed inside single-wall carbon nanotubes by vacuum annealing functionalized C59N molecules encapsulated inside the tubes. A hindered, anisotropic rotation of C59N was deduced from the temperature dependence of the electron spin resonance spectra near room temperature. Shortening of spin-lattice relaxation time, T_1, of C59N indicates a reversible charge transfer toward the host nanotubes above $\sim 350$ K. Bound C59N-C60 heterodimers are formed at lower temperatures when C60 is co-encapsulated with the functionalized C59N. In the 10-300 K range, T_1 of the heterodimer shows a relaxation dominated by the conduction electrons on the nanotubes.