Effects of Ag seed layer on the properties of CoCrPt/Ti perpendicular media : Exchange coupling constant, domain size and coercivity
Details
Several kinds of 2 nm metal layer (M=Al, Cu, Ni, Cr, Ag, Mg, Fe, Co, Pd, Au, Pt, Mo, and Hf) were sputtered to increase Hc an Ku of CoCrPt/Ti perpendicular media. Among them Ag was very effective to increase Hc of (Co_<78>Cr_<22>)_<100-x>Pt_x/Ti(x=14, 20) films when 2 nm Ag, 18 nm Ti layer and 10-20 nm CoCrPt films were subsequently sputtered on Corning 7059 glass at 400℃. However, the effect was more pronounced when thickness of (Co_<78>Cr_<22>)_<100-x>Pt_x film was reduced to 10 nm. In addition α dedecreased when Ag layer was used. The film thickness below which Ag was effective was reduced if Pt content was decreased to 14 at. %. However, normal XRD experiment revealed that Ag did not promote c-axis growth of Ti and CoCrPt layer in the perpendicular direction. In the MFM observation domain size was reduced when Ag layer was introduced, which showed that films with good c-axis alignment could give lower Hc and wide domain width becasuse of strong magnetic coupling between grains.
