Abstract
We investigated the dependence of giant tunnel magnetoresistance (TMR) on the thickness of an MgO barrier and on the annealing temperature of sputtered CoFeB/MgO/CoFeB magnetic tunnel junctions deposited on SiO2/Si wafers. The resistance-area product exponentially increases with MgO thickness, indicating that the quality of MgO barriers is high in the investigated thickness range of 1.15-2.4 nm. High-resolution transmission electron microscope images show that annealing at 375°C results in the formation of crystalline CoFeB/MgO/CoFeB structures, even though CoFeB electrodes are amorphous in the as-sputtered state. The TMR ratio increases with annealing temperature and is as high as 260% at room temperature and 403% at 5 K.
| Original language | English |
|---|---|
| Pages (from-to) | L587-L589 |
| Journal | Japanese Journal of Applied Physics, Part 2: Letters |
| Volume | 44 |
| Issue number | 16-19 |
| DOIs | |
| Publication status | Published - 2005 |
Keywords
- CoFeB
- Crystallization
- Magnetic tunnel junction
- MgO barrier
- Tunnel magnetoresistance effect
ASJC Scopus subject areas
- Engineering(all)
- Physics and Astronomy (miscellaneous)
- Physics and Astronomy(all)