Figure 1

(a) High resolution transmission electron microscope micrograph of a portion of an individual DWCNT, filled inside its inner shell with elongated nanoparticles. (b) Schematic representation of the device, consisting of a filled nanotube on top of an oxidized Si wafer (used as a back gate) and connected between source-drain electrodes (50 nm Pd). The typical junction length is 350 nm. Magnetic field is applied in plane and in the direction of the carbon nanotube. (c) Lock-in gate modulation of the device at 40 mK with zero source-drain bias ($V_{\mathrm{sd}}=0$).Reuse & Permissions

Figure 2

Gate-dependent hysteresis of MR. (a) Plot of differential resistance $R$ versus the magnetic field ($B$) from $-1.8$ to $+1.8\mathrm{T}$ (back and forth) at different gate voltages. At $V_g=-1.05\mathrm{V}$, $R$ jumps around $B=\pm 0.15\mathrm{T}$ with a sharp increase in resistance. At $V_g=-1.07\mathrm{V}$, no hysteresis is observed. At $V_g=-1.10\mathrm{V}$, $R$ jumps around $B=\pm 0.15\mathrm{T}$ with a sharp drop in resistance. (b) Gate modulation of the differential resistance ($R$) in the gate voltage range $V_g=-1.5\mathrm{V}$ to $V_g=-1\mathrm{V}$ at $B=0\mathrm{T}$. The color of the curve is related to the sign of its slope (red for positive and blue for negative). Indicated are the position of the gate voltages, where the plots of (a) were taken. (c) Hysteresis ($\Delta R$) plot (difference between trace and retrace) in the same gate voltage region. Positive, negative, and zero hysteresis is color plotted as red, blue, and white, respectively. The sign of the hysteresis after the jump (positive magnetic field) and the slope of the gate modulation are correlated.Reuse & Permissions

Figure 3

Magnetization reversal induced shift of the Coulomb peaks. (a) $R$ is color plotted for different $V_g$ and $B$ (traces from $-2$ to $+2\mathrm{T}$) in the same gate voltage region as in Fig. 2b. (b) Horizontal cuts in (a) showing a right shift ($\Delta V_g$) of 5 meV of the Coulomb oscillations after the switching field $B_{\mathrm{sw}}=\pm 0.15\mathrm{T}$.Reuse & Permissions

Figure 4

Magneto-Coulomb effect. (a) Equivalent electrical circuit of the device. The nanoparticle is isolated from the environment because it is encapsulated inside the inner wall of a DWCNT. The outer wall is coupled to the gate electrode via the capacitance $C_g$. The effective coupling between the outer wall of the nanotube and the nanoparticles is shown as a capacitance $C_{\mathrm{eff}}$. Only the outer wall conducts the current. (b) Schematic evolution of the effective charge $\Delta Q$ induced on the CNT by the Zeeman effect in the nanoparticle. $\Delta Q$ varies with applied magnetic field, until the nanoparticle switches its magnetization. At the switching field $B=\pm B_{\mathrm{sw}}$, $\Delta Q$ changes discontinuously. (c) Shift of the Coulomb diamonds due to switching of the nanoparticles.Reuse & Permissions