NiAl seed layer for obliquely sputtered thin-film tape

Two types of magnetic tape were produced by oblique sputtering with the incident angle of 65/spl plusmn/5/spl deg/. One consists of a 180-nm Cr underlayer layer and 20-nm Co layer. The other consists of a 90-nm NiAl seed layer, 90-nm Cr intermediate layer, and 20-nm Co layer. It is shown that the use of NiAl seed layer allows further reduction of the Co grain size and improves the film smoothness. The fine microstructure obtained in the NiAl seed layer resulted in smaller Co grains with more uniform size distribution. This caused the switching field distribution to become narrower, while the values of the squareness and coercivity remained high. The recording performances were also improved for the tape with NiAl seed layer.