Observation of strong Kondo like features and co-tunnelling in superparamagnetic GdCl3 filled 1D nanomagnets

Siphephile Ncube (1) , Chistopher Coleman (1) , Alvaro S. de Sousa (1) , Chunyang Nie (2) , Pierre Lonchambon (2) , Emmanuel Flahaut (2) , Andrew Strydom (3, 4) , Somnath Bhattacharyya (1)

1 WITS - University of the Witwatersrand [Johannesburg]
2 CIRIMAT - Centre interuniversitaire de recherche et d'ingenierie des matériaux
3 UJ - University of Johannesburg [South Africa]
4 CPfS - Max-Planck-Institut für Chemische Physik fester Stoffe

Filling of carbon nanotubes has been tailored over years to modify the exceptional properties of the 1-dimensional conductor for magnetic property based applications. Hence, such a system exploits the spin and charge property of the electron, analogous to a quantum conductor coupled to magnetic impurities, which poses an interesting scenario for the study of Kondo physics and related phenomena. We report on the electronic transport properties of MWNTs filled with GdCl3 nanomagnets, which clearly show the co-existence of Kondo correlation and cotunelling within the superparamagnetic limit. The Fermi liquid description of the Kondo effect and the interpolation scheme are fitted to the resistance-temperature dependence yielding the onset of the Kondo scattering temperature and a Kondo temperature for this nanocomposite, respectively. Cotunneling of conduction electrons interfering with a Kondo type interaction has been verified from the exponential decay of the intensity of the fano shaped nonzero bias anomalous conductance peaks, which also show strong resonant features observed only in GdCl3 filled MWNT devices. Hence, these features are explained in terms of magnetic coherence and spin-flip effects along with the competition between the Kondo effect and co-tunneling. This study raises a new possibility of tailoring magnetic interactions for spintronic applications in carbon nanotube systems.

Mots clés: Multi-walled Carbon Nanotubes; Gadolinium; 1D nanomagnets; Kondo effect; Superparamagnetic; Filling

Domaines: Science des matériaux [cond-mat.mtrl-sci]; Mécanique des matériaux [physics.class-ph]

Siphephile Ncube, Chistopher Coleman, Alvaro S. de Sousa, Chunyang Nie, Pierre Lonchambon, et al.. Observation of strong Kondo like features and co-tunnelling in superparamagnetic GdCl3 filled 1D nanomagnets. Journal of Applied Physics, 2018, vol. 123 (n° 21), pp. 213901/1-213901/7. ⟨10.1063/1.5024346⟩. ⟨hal-01812545⟩