| 摘要 |
A TMR sensor with a free layer having a FL1/FL2/FL3 configuration is disclosed in which FL1 is FeCo or a FeCo alloy with a thickness between 2 and 15 Angstroms. The FL2 layer is made of CoFeB or a CoFeB alloy having a thickness from 2 to 10 Angstroms. The FL3 layer is from 10 to 100 Angstroms thick and has a negativeλto offset the positiveλfrom FL1 and FL2 layers and is comprised of CoB or a CoBQ alloy where Q is one of Ni, Mn, Tb, W, Hf, Zr, Nb, and Si. Alternatively, the FL3 layer may be a composite such as CoB/CoFe, (CoB/CoFe)n where n is≧2 or (CoB/CoFe)m/CoB where m is≧1. The free layer described herein affords a high TMR ratio above 60% while achieving low values forλ(<5×10−6), RA (1.5 ohm/μm2), and Hc (<6 Oe).
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