Spin-valve heads with synthetic antiferromagnet CoFe/Ru/CoFe/IrMn

Spin-valve (SV) films Si(100)/Ta30/NiFe50/CoFe20/Cu26/ CoFe23/Ru7/CoFe20/Ir Mn50/Ta30 (in Angstrom) exhibit a room temperature (RT) giant magnetoresita nce (GMR) ratio of 8.5% with an effective exchange pinning field (H-eex) of similar to 1.3 kOe and an antiferromagnetic (AF) saturation field (Hs) of; similar to 6.0 kOe. The synthetic spin valve shows a GMR ratio of 5.0% at 150 degrees C with H-eex >500 Oe, while a conventional spin valve [Si(100)/ Ta50/NiFe50/CoFe20/Cu28/CoFe22/IrMn50/Ta50 in Angstrom] has a GMR ratio of 5.0% with H-ex,200 Oe. The synthetic sample also showed a superior thermal stability with a RT GMR value of 6.9% (compared to 6.1% for conventional sa mple) after an anneal at 250 degrees C for 10 h. Shielded narrow track synt hetic SV readers demonstrated high amplitude, large dynamic range, and exce llent magnetic stability, indicating extendibility for ultrahigh density re ad head applications. (C) 1999 American Institute of Physics. [S0021-8979(9 9)71308-3].