Noise in MgO barrier magnetic tunnel junctions with CoFeB electrodes: Influence of annealing temperature

Low frequency noise has been measured in magnetic tunnel junctions with MgO barriers and magnetoresistance values up to 235%. The authors investigated the noise for different degrees of crystallization and CoFeB∕MgO interface quality depending on the annealing temperature. The authors report an extremely low 1∕f noise, compared to magnetic junctions with Al2O3 barriers. The origin of the low frequency noise is discussed and it is attributed to localized charge traps with the MgO barriers.