Optimization of PM stabilization for balanced sensitivities and variations of spin valve heads

The control of variations of amplitude and symmetry of synthetic antiferromagnetic spin valve heads becomes increasingly difficult with the shrinking of head sizes. Micromagnetic Monte Carlo simulations were carried out to investigate the correlations between different head parameters and head performance variations. It was found that the head performance variation is strongly correlated with the permanent magnet stabilization strength. In addition, the magnetization orientation of the reference layer in the biasing state varies more from head to head than that of the free layer, when the sizes of the spin valve heads are in the deep-submicron range. The conflict between the head sensitivity and the head performance variation is clearly shown by the modeling results.