Tunnel magnetoresistance enhancement in ferromagnetic tunnel junctions with ferromagnetic nano-particle layer insertion

Abstract

Coulomb blockade dominates the electron transport in an ultra-small double tunnel junction. Here, a helicon sputtering deposition system is used to fabricated Co/sub 90/Fe/sub 10//AlO/sub x//Co/sub 90/Fe/sub 10//AlO/sub x//Co/sub 90/Fe/sub 10/ MDTJs. The enhancement of TMR ratio within the Coulomb blockade regime. TMR curves across the MDTJs show a superparamagnetic behavior. It was also observed that the bias voltage dependence of the TMR becomes broader above 50 K, and the enhancement of the TMR around zero bias disappears at room temperature.