Investigation of magnetic and electronic coupling between two (Ga,Mn)As layers in (Ga,Mn)As/GaAs/(Ga,Mn)As magnetic tunnel junctions

摘要

The coupling between the two magnetic layers in a series of (Ga, Mn)As/GaAs/(Ga,Mn)As magnetic tunnel junctions with different nonmagnetic spacer thicknesses t_(NM) were studied by magnetization and planar Hall effect (PHE) measurements. The PHE data indicate that the magnetization reversals of the two layers are strongly correlated when the t_(NM) is less than 3 nm and are independent when t_(NM) is larger than 15 nm. From the results, it is concluded that considerable redistribution of hole wave functions plays a major role for small t_(NM). The PHE results for the sample with 6 nm spacer also suggest an antiferromagnetic interlayer exchange coupling.