Thermal activation effects in CoCrPtTa media due to stacking faults

We report magnetic measurements made on two CoCrPtTa thin film media, which were sputter deposited in identical conditions onto either CrMn or NiAl/Cr Mn underlayers grown on glass substrates. This produced films with [11 (2) over bar0] and [10 (1) over bar0] preferred orientations respectively. The films had stacking fault densities of 8 +/- 1% and 13 +/- 1 % respectively. Increased magnetic viscosity and switching at low fields in the switching field distributions were observed which correlates well with the level of f cc-like regions. We find that the energy barriers to reversal in these film s are dominated by the anisotropy field distribution rather than the distri bution of grain-sizes. Furthermore, it is clear that even relatively low le vels of stacking faults cause significant levels of thermally activated mag netization reversal which may cause reduced thermal stability of written in formation.