A study on magnetic properties and structure of SmCo5 thin films on Ni–W underlayers

A systematic study on Ni–W alloy underlayers has shown that a highly textured (2 1 1)-Ni4W can be formed after deposition at room temperature. Highly textured (0 0 0 1)-SmCo5 with a high out-of-plane coercivity (over 10 kOe) and large perpendicular anisotropy can be obtained after deposition on the (2 2 1)-Ni4W underlayer probably due to a small mismatch between (2 2 1)-Ni4W and (0 0 0 1)-SmCo5. Our study indicates that the surface roughness of the underlayers also plays a crucial role, that a smooth surface is favorable for a good crystallinity and high coercivity of SmCo5. Moreover, we found that a highly textured Ni-(1 1 1) can be obtained on the top of the (2 1 1)-textured Ni4W. The film structure of SmCo5/Ni/Ni4W may be interesting as the hard/soft double-layered film for perpendicular magnetic recording or for other applications after a further development.