NiFe/CoFeB spin-valve heads for over 5 Gbit/in2 density recording

This paper outlines the successful use of NiFe/(Co₉₀Fe ₁₀)_100-xBx (x=5, 10%) for soft magnetic, thermally stabilized spin-valves. The GMR effect in the NiFe/CoFeB spinvalve increases after annealing. The annealing effect of CoFeB on CoFeB/Cu interfaces is investigated by high resolution TEM-EDX analysis. Merged inductive NiFe/CoFeB spin-valve heads with a read gap length of 0.18 μm and a write gap length of 0.28 μm having NiO(400 Å)/NiFe(10 Å)/CoFeB₅(10 Å)/Cu(32 Å)/CoFeB₅(20 Å)/Ta(100 Å) spin-valve film and high Bs laminated FeZrN/NiFe top poles were fabricated. Their read/write performance were tested on a low noise CoCr₁₉Pt ₅Ta₂Nb₂ thin-film disk with an Mrt of 0.6 memu/cm² and a coercivity of 2600 Oe. A normalized output per track-width of 1000 μVpp/μm and a 50% rolloff linear density (D₅₀) of 182 kFCI is obtained. This performance well exceeds the performance of 5 Gbit/in² spin-valve heads. The measured S/N was 26.8 dB for a spin-valve head with with a narrow read track-width of 0.68 μm, and the feasibility of 8 G bit/in² recording density is studied using a 1/7 code Narrow Band PRML channel