Enhanced tunnel magnetoresistance in fully epitaxial ZnO:Co-based magnetic tunnel junctions with Mg-doped ZnO barrier

摘要

The fully epitaxial ZnO-based ZnO:Co/ZnO:Mg/ZnO:Co magnetic tunnel junctions were grown on Al2O3(0001) substrate by oxygen plasma-assisted molecular beam epitaxy. The magnetoresistance behavior and spin injection through ZnO:Mg barrier were investigated. An enhanced positive tunnel magnetoresistance ratio of 85.6% is observed at 1.8 T at 5 K. The junction resistance at zero magnetic field is linear with respect to temperature power law T-4/3 between 5 K and 70 K, indicating that carriers tunnel through ZnO:Mg barrier via two localized states.