We have investigated the spin tunneling transport in magnetic tunnel junctions (MTJs) with Co40 Fe40 B20, Co50 Fe50, and Co90 Fe10 free layers which were deposited on the lower electrode consisting of the same Co40 Fe40 B20 reference layer/MgO barrier. The tunnel magnetoresistance (TMR) ratio depends critically on the choice of the free layer; the TMR ratios up to 355% were obtained for the MTJs with Co40 Fe40 B20 free layers and up to 277% with Co50 Fe50 free layers, both of which have highly (001)-oriented bcc structures. No high TMR ratio was observed for the MTJs with Co90 Fe10 free layer having a polycrystalline fcc structure.
ASJC Scopus subject areas
- Physics and Astronomy(all)