A magnetic and microstructural study on high rate evaporated Co-Cr films with Ti underlayer

Co-Cr films have been E-B evaporated at a deposition rate of 400nm/s with a Ti underlayer on heat resistant polymer substrates.
Hc\perp
of the films increases steeply with increasing film thickness, taking the maximum at about 50nm, followed by a gradual decrease as the thickness further increases. Coercivities measured by polar Kerr effect of both top and bottom surfaces are substantially the same as those by VSM. Thus the magnetization reversal is considered to be macroscopically coherent throughout the film thickness. Sectional TEM observations reveals that columnar structures of about 20nm in diameter stretch directly from Ti interface throughout the film thickness. No separate initial layer is observed. The columns are characterized by dense stacking faults of hcp c-plane, and contact with each other through hcp - hcp grain boundaries, where neither non-magnetic secondary phases like sigma phase nor voids are recognized.