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Recently, the developments of the spintronics devices have been well expanded. The behaviors of the basic unit part in the magnetic devices are dependence on many factors, among which crystal structure and thermal stability of magnetic films play an important role. Suitable buffer layer is needed for antiferromagnetic (AFM) layer to induce the FM/AFM coupling in magnetic tunnel junction (MTJ) or spin valve (SV) structures. In this article, we extend our previous works [1] to investigate the characterization of the Osmium (Os) in a textured magnetic multi-layer structure system. The properties and characterization of buffer layer and diffusion barrier using Os are reported. A textured structure of Ta/ CoFe 10/ Os (d)/ IrMn 30/ Os 30/ Cu 30/ Si (100) were grown by magnetron sputtering, where thickness was in nm, and d was varied from 0 to 1 nm. After deposition, all samples were subjected to magnetic field annealing at 3 kOe and at different temperatures for 30 min. Magneto-Optical Kerr Effect (MOKE) and vibrating sample magnetometer (VSM) were used to examine the magnetic behavior, while the crystal structure was studied by X-ray diffraction (XRD).The Cu (002)/ Si (100) epitaxy seed layer was prepared by metal-metal epitaxy on silicon (MMES) method [2]. As shown in fig. 1 that a strong Os (0002) peak indicating Os/Cu was highly oriented, and all other metal films in this study growing on top of it still exhibits good crystalline structure. Since Os is hexagonal closed packed (hcp) structure, and the (0002) surface is the same to the fcc (111). Magnetic films of NiFe, CoFe and IrMn could grow as an fcc (111) surface which is parallel to the Os (0002), for obtaining higher exchange bias [3]. The dependences of exchange field (H ex ) and annealing temperature are shown in fig. 2. The non-textured and textured samples both obtain maximum H ex after annealed at 200 °C. The H ex of the non-textured samples degraded rapidly after annealed at temperature higher than 200 °C. The H ex of the textured samples vanishes at 350 °C, moreover, a thin additional Os barrier between the CoFe and IrMn layers could also improve the thermal stability obviously. The H ex of CoFe/Os 0.3/IrMn has a maximum at 250 °C, but vanishes at 400 °C. Sample with 1.0 nm of Os also showed a maximum H ex of 15 Oe at 250 °C; however, H ex does not go to zero even at an annealing temperature of 400 °C. It is also found that 1.0 nm Os barrier was too thick for CoFe/IrMn to retain the H ex .In summary, a textured structure of Ta/ CoFe/ Os (d)/ IrMn has been grown on Os (0002)/Cu (002) seed layer by MMES method. A thin Os barrier could stabilize the CoFe/IrMn at high temperature. H ex is also varied with annealing temperature and the thickness of Os. No exchange bias was observed with d м 1nm.[1] T. Fig. 1 The XRD diffraction patterns of the Os (0002)/Cu (002) and Cu (002) seed layer, respectively. The high orientation seed layer could be obtained by MMES method at room temperature. Fig.2 The exchange field of non-textured, textured, and textured with barr...