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/CrMn underlayers grown on glass substrates. This produced films with [112~0] and [101~0] preferred orientations respectively. The films had stacking fault densities of 8/spl plusmn/1% and 13/spl plusmn/1% respectively. Increased magnetic viscosity and switching at low fields in the switching field distributions were observed which correlates well with the level of FCC-like regions. We find that the energy barriers to reversal in these films are dominated by the anisotropy field distribution rather than the distribution of grain-sizes. Furthermore, it is clear that even relatively low levels of stacking faults cause significant levels of thermally activated magnetization reversal which may cause reduced thermal stability of written information.