Spin-valve sensors exchange-biased by ultrathin TbCo films

Abstract

Ultrathin TbCo films are used to exchange-bias spin-valve sensors as an alternative to the commonly used FeMn films. Magnetoresistance values of 7.8% and sensitivities of 2.5%/Oe are demonstrated for spin-valve stripes where the pinned NiFe layer is exchange biased by a 120-Å thick TbCo film. The exchange field can be fine tuned by changing the TbCo layer thickness. A well-biased and linear spin-valve sensor was fabricated, with a height of 2 μm and a trackwidth of 25 μm, where the free layer is biased by the sense current.