We investigated the relationship between the tunnel magnetoresistance (TMR) ratio and the electrode structure in MgO-barrier magnetic tunnel junctions (MTJs). The TMR ratio in an MTJ with Co40Fe40B20 reference and free layers reached 355% at the post-deposition annealing temperature of Ta=400 °C. When Co50Fe50 or Co90Fe10 is used for the reference layer material, no high TMR ratio was observed. The key to have high TMR ratio is to have highly oriented (0 0 1) MgO barrier/CoFeB crystalline electrodes. The highest TMR ratio obtained so far is 450% at Ta=450 °C in a pseudo-spin-valve MTJ.
- MgO barrier
- Tunnel magnetoresistance
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics