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Rear End AFM Pinned Bias Layer for Flux Guided Tunnel Valve Disclosure Number: IPCOM000013839D
Original Publication Date: 2001-Mar-01
Included in the Prior Art Database: 2003-Jun-18

Publishing Venue



An exchange pinned ferromagnetic layer is placed at the rear end of the Tunnel Valve sensor to provide magnetic bias to the free layer. The ferromagnetic layer is magnetized so that the magnetization forms perpendicular angle with the bias/free layer boundary. Futhermore, the bias layer is insulated from the sensor so that it does not shunt current flowing in the Tunnel Valve. The direction of the bias layer magnetization is selected so that its bias field (Hb) adds to the pinned film demagnetizing field. To achieve proper biasing of the Tunnel Valve free layer magnetization, the sum of the bias field (Hb), the pinned film demagnetizing field (Hd), ferromagnetic coupling field at the free layer (Hfc) is set to zero (Hd+Hfc+Hb 0). For the sensor using antiparallel pinning for the pinned layer, the setting field direction for the pinning layer is the same as for the bias layer pinning. 1