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Tunnel Valve Coupling Field Reduction using Dual TV with Half-metallic nanolayer Disclosure Number: IPCOM000015550D
Original Publication Date: 2002-Jan-07
Included in the Prior Art Database: 2003-Jun-20

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We disclose a new structure for Tunnel Valve sensor to minimize the ferromagnetic coupling between the Free and the pinned layers. The structure is as follows: PtMn/CoFe/Fe3O4/barrier/Free layer/barrier/CoFe/Ru/CoFe/PtMn. The barrier layers are any suitable barriers such as Al2O3 or MgO. The antiferromagnetic films PtMn are set so that the ferromagnetic layers next to barriers Fe3O4 on left and CoFe on right side are set 180 degree opposite in phase. Since the magnetoresistance through spin polarized tunneling has opposite sign for Fe3O4 and CoFe, the magnetoresistance signals add for these layers. Since the magnetization of the reference layers near barriers (Fe3O4 and CoFe) are 180 degree opposite in phase, the ferromagnetic coulping of these layers with the free layer cancel. 1