Thermal stability of MTJ using Zr capping layer

The simple stacking structure such as [Sub/Zr/AlO/sub x//NiFe (or CoFeB)/capping layer] was prepared to investigate the changes of magnetic properties of free layer with annealing temperature. Ta, Ru, or Zr was used as the capping layer. Samples were annealed in a vacuum (below 1/spl times/10/sup -6/ Torr) for 1 hour under a magnetic field of 10 KOe. The magnetic properties were measured using vibrating sample magnetometer in sample with 1/spl times/1 cm/sup 2/ area. The changes of the coupling field between the pinned layers through Ru as a function of annealing temperature for various pinned layer materials were also studied.