Realization of extreme tunnel magnetoresistance with a molecule-magnet-dimer junction

Abstract

By means of the Rate equation approach in the sequential tunneling regime, we study spin-polarized transport through a molecule magnet dimer of both ferromagnetic (FM) and antiferromagnetic (AFM) types, which is weakly coupled to collinear FM leads. We pay particular attention to the effect of spin exchange interactions between electron spin and the molecule magnet on the tunnel magnetoresistance (TMR). Giant positive TMR is found in the positive bias with the AFM dimer. Particularly we are able to realize the negative TMR of theoretical lowest limit. And thus the molecule dimer device acts as an ideal valve to blockade completely the current channel of parallel configuration of electrode polarizations.