The influence of the tantalum buffer layer on the magnetic anisotropy of perpendicular Co-Fe-B/MgO based magnetic tunnel junctions is studied using magneto-optical Kerr-spectroscopy. Samples without a tantalum buffer are found to exhibit no perpendicular magnetization. The transport of boron into the tantalum buffer is considered to play an important role on the switching currents of those devices. With the optimized layer stack of a perpendicular tunnel junction, a minimal critical switching current density of only 9.3kA/cm2 is observed and the thermally activated switching probability distribution is discussed.
Bibliographical notePublisher Copyright:
© 2015 The Japan Institute of Metals and Materials.
- Current induced switching
- Magnetic tunnel junctions
- Néel-Brown law
- Perpendicular anisotropy
- Spin-transfer torque