公开(公告)号：JPH0855312A

公开(公告)日：1996-02-27

申请号：JP10632294

申请日：1994-04-22

Applicant: IBM

Inventor： CAIN WILLIAM CHARLES ,  HEIM DAVID E ,  WANG PO-KANG

IPC: G01R33/09 ,  G11B5/31 ,  G11B5/39 ,  H01L43/08 ,  H01L43/10

Abstract: PURPOSE: To obtain a constant field generated by ferromagnetic exchange coupling and a current and thus enable appropriate offset of influence thereof, by additionally providing a magnetic flux keeper layer and a spacer layer in a spin valve structure. CONSTITUTION: A magnetoresistive sensor 20 has a layered spin valve structure, including first and second thin layers 28, 34 of a ferromagnetic material and separated from each other by a spacer layer 32 of a non-magnetic metal. With a zero-application magnetic field, the direction of magnetization of the first layer 28 is caused to be in parallel to the longitudinal axis of the sensor 20 and perpendicular to the fixed direction of magnetization of the second layer 34. In addition, a thin magnetic flux keeper layer 24 is provided which is separated by the spacer layer 32 and has a fixed direction of magnetization opposite to the direction of magnetization of the second layer 34 and a product of thickness of the substantially same moment as the second layer to offset a static magnetic field from the second layer 34. A power source 48 causes a current to flow via the sensor 20 so as to generate a magnetic field offsetting ferromagnetic exchange coupling between the first and second layers 28, 34. Detection means 50 detects fluctuations in the resistance of the sensor 20 due to the difference in the rotation of magnetic fields of the first and second layers 28, 34.

公开(公告)号：CA1236569A

公开(公告)日：1988-05-10

申请号：CA496162

申请日：1985-11-26

Applicant: IBM

Inventor： HEIM DAVID E

IPC: G11B5/09 ,  G11B5/127 ,  G11B5/17 ,  G11B5/265 ,  G11B5/31 ,  G11B15/12

Abstract: THREE POLE SINGLE ELEMENT MAGNETIC READ/WRITE HEAD A magnetic head has three pole pieces that form a magnetic circuit. The magnetic pole pieces are arranged in a common plane so that the two outside pole pieces are each spaced from the central pole piece to form a transducing gap between each of the outside pole pieces and the central pole piece. A first and a second coil, each having the same magnetic sense is wound on the magnetic structure between an outside and the center pole piece. The coils are connected in series for a write operation so that the flux in the outside pole pieces is additive for writing, and the coils are connected in series opposition for a read operation so that the flux produced in the center pole by a previously recorded magnetic transition in the magnetic recording medium adjacent to the transducing gaps is sensed additively in the coils.