Improved tunnel magnetoresistance of magnetic tunnel junctions with Heusler Co_2FeAI_(0.5)Si_(0.5) electrodes fabricated by molecular beam epitaxy

摘要

The authors have developed a magnetic tunnel junction of Co_2FeAl_(0.5)Si_(0.5) electrodes and a MgO barrier fabricated by molecular beam epitaxy and observed that this device had a tunnel magnetoresistance ratio of 386% at approximately 300 K and 832% at 9 K. The lower Co_2FeAl_(0.5)Si_(0.5) electrode was annealed during and after deposition resulting in a highly ordered structure with small roughness. This highly ordered structure could be obtained by annealing treatment even at low temperatures. Furthermore, a weak temperature dependence of the tunnel magnetoresistance ratio was observed for the developed magnetic tunnel junction.