Enhancement of exchange field in CoFeIrMn by OsCu buffer layer

Enhancement of exchange field (Hex) and thermal stability of the textured CoFeIrMn with OsCu buffer layer and Os diffusion barrier layer were studied. As revealed by x-ray Diffraction (XRD), an Os (0002) surface mesh was observed to form on Cu (100)/Si (100). The growth of CoFe (111)/IrMn (111) on such a template is parallel to the Os (0002). With the OsCu buffer layer, the CoFeIrMn presents an enhancement of 70 Oe on Hex larger than that without OsCu. The Hex of the textured sample was 230 Oe at room temperature and it was increased to 330 Oe after 250 °C annealing. When the temperature reached 350 °C, Hex vanished. The increment of the temperature at which the textured and the nontextured sample obtaining their maximum Hex and the vanishing temperature of Hex were 50 and 75 °C, respectively. Furthermore, the CoFeOs (d) IrMn slowed down the Hex degradation. The sample with d=0.3 nm obtained its maximum Hex at 250 °C and vanished when it reached 400 °C. The combination of CoFeIrMn with OsCu buffer layer and Os barrier layer made the Hex higher and also better thermal stability.