Quasi-static and dynamic analysis of spin valve tape heads with synthetic free and pinned layers versus heads with a conventional free layer and a synthetic pinned layer

A comparative analysis of tape heads with two spin-valve designs is presented: spin valves with synthetic free and pinned layers (SF-SAF/AF) versus spin valves with a conventional free layer and a synthetic pinned layer (SAF/AF). The SF layer, corresponding to a smaller free layer's effective magnetic thickness ([t.sub.eff,SF] ~ 28 [Angstrom]) and lower magnetic moment ([M.sub.eff,SF] ~ 398 emu/cc), is more sensitive to the field flux from the medium and has a higher sensitivity (~ 3.4 mV/[micro]m) than the conventional NiFe/CoFe free layer, with D50 ~ 130-138 kfci, in comparison with D50 ~ 99 kfci for SAF/AF spin-valve heads. Thick media limitations become visible on the heads' performance above ~ 112 kfci and the heads are shown to be mostly time-instability free. Index Terms--Head characterization, magnetic read heads, spin valves, synthetic ferrimagnets/antiferromagnets.