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

Abstract

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 mag netic 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 GdCl 3 nano magnets, 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 scatter ing temperature and a Kondo temperature for this nanocomposite, respectively. Cotunneling of conduction electrons interfering with a Kondo type interaction has been verified from the exponen tial decay of the intensity of the fano shaped nonzero bias anomalous conductance peaks, which also show strong resonant features observed only in GdCl 3 filled MWNT devices. Hence, these fea tures 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.

Tuning Magnetic Properties of a Carbon Nanotube-Lanthanide Hybrid Molecular Complex through Controlled Functionalization

“…As shown in Figure 6b, we determine Kondo onset temperatures (T K ) [31,32] of 132, 155, 188 and 202 K as a function on increasing Gd concentration. These findings are in agreement with the analysis of the Raman deconvolution study and shed light onto how structural degradation and magnetic loading can lead to enhanced spin correlations in functionalized carbon systems as recently demonstrated through the observation of the impurity Kondo effect [33][34][35]. Furthermore, these findings are significant as they help explain the role of itinerate electrons in mediating the interaction between spatially separated spin centers and thus may provide a mechanism for tuning the system from a superparamagnetic material to a highly correlated system with a definite spin texture.…”

Structure of inorganic nanocrystals confined within carbon nanotubes

“…In the case of iron oxide, superparamagnetic nanowires were stabilized within DWCNTs [73], also leading to magneto-Coulomb effects [74]. DWCNTs Filled with Gadolinium exhibited Kondo effect and enhanced magnetic properties [75,76].…”

Proximity Effect-Induced Magnetoresistance Enhancement in a Fe3GeTe2/NbSe2/Fe3GeTe2 Magnetic Tunnel Junction

“…Increasing the voltage to V 2 raises E F1 to E F2 which is in the energy band. The electrons injected into the NbSe 2 layer can pass through freely by the cotunnelling effect31 without changing the spin polarizability. Consequently, the device shows an MTJ behavior and its MR remains unchanged in the temperature range below T C .…”