Richard P. Michel

Effect of pinning field on the magnetization in patterned synthetic antiferromagnetic spin valves

The effect of the pinning field (Hp) on the distribution of the average magnetization direction in the pinned layer (PL) and the reference layer (RL) of spin valve (SV) sensors with synthetic antiferromagnetic layers was investigated with respect to the magnetic fields that can cause canting in the PL and RL magnetization. Hp was controlled by annealing temperatures and seed layers. It was found that the direction of the average magnetization in the PL and RL is largely governed by shape anisotropy in the patterned SV sensors with a low Hp. Both experimental and modeling results support the idea that the canting of the PL and RL can occur in both SV sheet films and patterned SV sensors, when Hp is not large enough to overcome the interfacial magnetostatic coupling (H1) between the free and reference layer.

Micromagnetic recording model of writer geometry effects at skew

The effects of the pole-tip geometry at the air-bearing surface on perpendicular recording at a skew angle are examined through modeling and spin-stand test data. Head fields generated by the finite element method were used to record transitions within our previously described micromagnetic recording model. Write-field contours for a variety of square, rectangular, and trapezoidal pole shapes were evaluated to determine the impact of geometry on field contours. Comparing results for recorded track width, transition width, and media signal to noise ratio at 0° and 15° skew demonstrate the benefits of trapezoidal and reduced aspect-ratio pole shapes. Consistency between these modeled results and test data is demonstrated.