Effect of gaas intermediary layer thickness on the properties of (Ga,Mn) as tri-layer structures

Abstract

We have investigated the magnetic properties, current–voltage characteristics, and tunnel magnetoresistance of (Ga,Mn)As/GaAs/(Ga,Mn)As tri-layers having different thickness of the intermediary GaAs layer (1–7 nm). When the thickness of GaAs layer is less than 6 nm, the two (Ga,Mn)As layers couples ferromagnetically. For the tri-layers with thicker GaAs, the GaAs acts as an effective barrier for the carrier transport and decouples the two (Ga,Mn)As layers, which results in tunnel magnetoresistance ratio as high as 100% at 5 K.