公开(公告)号：SG67574A1

公开(公告)日：1999-09-21

申请号：SG1998004212

申请日：1998-10-15

Applicant: IBM

Inventor： DILL FREDERICK HAYES ,  FONTANA ROBERT EDWARD JR ,  PARKIN STUART STEPHEN PAPWORTH ,  TSANG CHING HWA

IPC: G11B5/33 ,  H01F10/16 ,  G11B5/39 ,  H01F10/32 ,  H01L43/08

Abstract: A magnetic tunnel junction (MTJ) magnetoresistive read head for a magnetic recording system has the MTJ device (110,120,130) located between two spaced-apart magnetic shields (S1,S2). The magnetic shields, which allow the head to detect individual magnetic transitions from the magnetic recording medium without interference from neighboring transitions. also function as electrical leads for connection of the head to sense circuitry. Electrically conductive spacer layers (102,104) are located at the top and bottom of the MTJ device and connect the MTJ device to the shields. The thickness of the spacer layers is selected to optimize the spacing between the shields, which is a parameter that controls the linear resolution of the data that can be read from the magnetic recording medium. To reduce the likelihood of electrical shorting between the shields if the shield-to-shield spacing is too small, each of the shields can have a pedestal region (161,163) with the MTJ device located between the two pedestals, so that the shield-to-shield spacing outside the pedestal regions is greater than in the pedestal regions.

公开(公告)号：SG60136A1

公开(公告)日：1999-02-22

申请号：SG1997003873

申请日：1997-10-27

Applicant: IBM

Inventor： FONTANA ROBERT EDWARD JR ,  PARKIN STUART STEPHEN PAPWORTH

IPC: G01R33/09 ,  G11B5/39 ,  G11C11/16 ,  H01L43/08

Abstract: A magnetic tunnel junction device for use as a magnetic memory cell or a magnetic field sensor has one fixed ferromagnetic layer and one sensing ferromagnetic layer formed on opposite sides of the insulating tunnel barrier layer, and a hard biasing ferromagnetic layer that is electrically insulated from but yet magnetostatically coupled with the sensing ferromagnetic layer. The magnetic tunnel junction in the device is formed on an electrical lead on a substrate and is made up of a stack of layers. The layers in the stack are an antiferromagnetic layer, a fixed ferromagnetic layer exchange biased with the antfferromagnetic layer so that its magnetic moment cannot rotate in the presence of an applied magnetic field, an insulating tunnel barrier layer in contact with the fixed ferromagnetic layer, and a sensing ferromagnetic layer in contact with the tunnel barrier layer and whose magnetic moment is free to rotate in the presence of an applied magnetic field. The stack is generally rectangularly shaped with parallel side edges. A layer of hard biasing ferromagnetic material is located near to but spaced from the side edges of the sensing ferromagnetic layer to longitudinally bias the magnetic moment of the sensing ferromagnetic layer in a preferred direction. A layer of electrically insulating material isolates the hard biasing material from the electrical lead and the sensing ferromagnetic layer so that sense current is not shunted to the hard biasing material but is allowed to flow perpendicularly through the layers in the stack.

公开(公告)号：SG44397A1

公开(公告)日：1997-12-19

申请号：SG1996000143

申请日：1992-08-21

Applicant: IBM

Inventor： DIENY AMERICA BERNARD ,  GURNEY BRUCE ALVIN ,  PARKIN STUART STEPHEN PAPWORTH ,  SANDERS IAN LEWIS ,  SPERIOSU VIRGIL SIMON ,  WILHOIT DENNIS RICHARD

IPC: G11B5/39 ,  G01R33/09 ,  G01R33/06 ,  H01F10/10 ,  H01F10/08

Abstract: A magnetoresistive sensor comprising a layered structure having at least one bilayer comprising a first thin film of ferromagnetic material in interfacial contact with a second thin film of nonferromagnetic metallic material, characterised by the bilayer comprising a third thin film of material within said first thin film of ferromagnetic material, said third thin film having a thickness of between a fraction of a monolayer and several monolayers and being located at a predetermined distance x from the interface between said first and said second thin film layers.

公开(公告)号：SG42342A1

公开(公告)日：1997-08-15

申请号：SG1996001706

申请日：1992-02-07

Applicant: IBM

Inventor： DIENY BERNARD ,  GURNEY BRUCE ALVIN ,  METIN SERHAT ,  PARKIN STUART STEPHEN PAPWORTH ,  SPERIOSU VIRGIL SIMON

IPC: G01R33/09 ,  G11B5/39 ,  H01F10/08 ,  H01F10/16 ,  H01F10/32 ,  H01L43/10

Abstract: A magnetoresistive (MR) sensor comprising a layered structure formed on a substrate (11) includes a first (12) and a second (16) thin film layer (14) of magnetic material separated by a thin film layer of non-magnetic metallic material such as Cu, Au, or Ag, with at least one of the layers of ferromagnetic material formed of either cobalt or a cobalt alloy. The magnetization direction of the first ferromagnetic layer, at zero applied field, is set substantially perpendicular to the magnetization direction of the second ferromagnetic layer which is fixed in position. A current flow is produced through the sensor, and the variations in voltage across the MR sensor are sensed due to the changes in resistance produced by rotation of the magnetization in the front layer of ferromagnetic material as a function of the magnetic field being sensed.