The effect of sputter-deposition conditions on the coercive force in amorphous rare-earth-transition-metal thin films

The origins of the coercive force in amorphous rare-earth-transition metal films have been investigated. The results are discussed in terms of how the growth conditions of the sputter-deposited films determine the pinning features that cause the coercive force. A model has been developed for the variation of coercive force with film thickness that enables a local pinning force per unit area to be deduced. This suggests that it should be possible to increase the coercive force by breaking up the microstructure with a multilayered structure. An increase in coercive force obtained by making such structures with tungsten is described. A reduction in coercive force obtained when the films are deposited in the presence of a perpendicular magnetic field is also reported and interpreted in terms of a growth annealing model