Magnetic property and microstructure dependence of CoCrTa/Cr media on substrate temperature and bias

Thin CoCrTa/Cr films were deposited at different substrate temperature T_s and substrate biasing voltage V _b. The in-plane coercivity increased significantly with T_S and V_b. Coercive squareness and orientation ratio also increased with T_s and V_b. Transmission electron microscopy (TEM) results indicated that, at low T_s, the magnetic film had an isolated-grain structure, with smaller sub-grain structure within each grain. At high T_s, the magnetic film had a closely packed grain structure, probably due to the enhanced adatom mobility; the grain size was much larger and striations were observed in many grains. The application of a negative biasing voltage to the substrate also tended to reduce the grain isolation. At high T_s, it seems that biasing also reduced the number of grains with striations. Scanning electron microscopy (SEM) results indicated that, with increasing T_s and V _b, more high-frequency texture line appeared in the magnetic layer, which was likely related to the increase of orientation ratio and squareness with increasing T_s and V_b