Tunnel magnetoresistance in the $\hbox {B}_{n}\hbox {N}_{n }(n = 12, 24)$ cages

Abstract

In this study, the effects of the type of the cage, the bias and gate voltages on spin transport properties of electrons in magnetic tunnel junction (MTJ) of $\hbox {B}_{n}\hbox {N}_{n }(n = 12, 24)$ cages were investigated by theoretical methods. For a gate voltage ($V_{\mathrm{g}}$) more than 0.5 V, the device became electrically conductive at $V_{\mathrm{b}}= 0.5~\hbox {V}$. The electric current increased linearly for bias voltages more than $|V_{\mathrm{b}}|=1~\hbox {V}$ at $V_{\mathrm{g}} = 0.0~\hbox {V}$. The maximum value of the tunnel magnetic resistance (TMR) ratio was $\sim 75\%$ for $\hbox {B}_{12}\hbox {N}_{12}$ and 60% for $\hbox {B}_{24}\hbox {N}_{24}$ molecules. The maximum values of TMR against the bias voltage ($V_{\mathrm{b}})$ were seen at 1.6 V (−1.6 V) for $\hbox {B}_{12}\hbox {N}_{12}$ and 0.0 V for $\hbox {B}_{24}\hbox {N}_{24}$. At $V_{\mathrm{b}} = 0.5~\hbox {V}$, the TMR ratio was changed by varying the gate voltage. Finally, the spin transport properties of the $\hbox {B}_{12}\hbox {N}_{12}$ cage were compared with those of the $\hbox {B}_{24}\hbox {N}_{24}$ and $\hbox {C}_{60}$ cages.