公开(公告)号：SG46731A1

公开(公告)日：1998-02-20

申请号：SG1996009674

申请日：1996-05-02

Applicant: IBM

Inventor： FONTANA ROBERT EDWARD JR ,  GURNEY BRUCE ALVIN ,  LIN TSANN ,  SPERIOSU VIRGIL SIMON ,  TSANG CHING HWA ,  WILHOIT DENNIS RICHARD

IPC: G01R33/09 ,  G11B5/39 ,  H01F10/32 ,  H01L43/10 ,  H01L27/20 ,  G11C11/16

Abstract: A spin valve magnetoresistive (SVMR) sensor uses a laminated antiparallel (AP) pinned layer 70 in combination with an improved antiferromagnetic (AF) exchange biasing layer 57. The pinned layer comprises two ferromagnetic films 72, 74 separated by a nonmagnetic coupling film 73 such that the magnetizations of the two ferromagnetic films are strongly coupled together antiferromagnetically in an antiparallel orientation. This laminated AP pinned layer is magnetically rigid in the small field excitations required to rotate the SVMR sensor's free layer. When the magnetic moments of the two ferromagnetic layers in this AP pinned layer are nearly the same, the net magnetic moment of the pinned layer is small. However, the exchange field is correspondingly large because it is inversely proportional to the net magnetic moment. The laminated AP pinned layer has its magnetization fixed or pinned by an AF material that is highly corrosion resistant but that has an exchange anisotropy too low to be usable in conventional SVMR sensors. In the preferred embodiment the AF layer is nickel-oxide and is formed on one of the magnetoresistive (MR) shields that serves as the substrate 45. Thus the AF material also serves as the insulating MR gap material. The location of the AF layer and the laminated AP-pinned layer to which it is exchange coupled on the bottom of the SVMR sensor allows for improved longitudinal biasing of the free layer when the SVMR sensor is fabricated.

公开(公告)号：CA2158304A1

公开(公告)日：1996-05-05

申请号：CA2158304

申请日：1995-09-14

Applicant: IBM

Inventor： DOVEK MORIS MUSA ,  FONTANA ROBERT EDWARD JR ,  SPERIOSU VIRGIL SIMON ,  SPONG JACQUELIN KETNER

IPC: G01R33/09 ,  H01L43/08

Abstract: A magnetic field sensor uses four individual magnetoresistive spin valve elements electrically connected in a bridge circuit. The spin valve elements are lithographically formed on the same substrate with their free layers having their magnetization axes parallel to one another. An electrically conductive fixing layer is formed on the substrate but is insulated from the spin valve elements. The application of current through the fixing conductor during fabrication of the field sensor fixes the direction of magnetization of two of the pinned layers to be antiparallel to the direction of magnetization of the other two pinned layers. The bridge circuit output voltage is responsive to an external magnetic field in the plane of the sensor. By appropriate fixing of the direction of magnetization of the pinned layers during sensor fabrication, and appropriate connection to the input and output leads, the bridge circuit output voltage is a measure of either the magnetic field or field gradient. The fixing conductor, or a separate current strap formed on the substrate, can be used to pass an unknown current over the sensor, in which case the bridge circuit output voltage is a measure of the unknown current.