公开(公告)号：JPH11213351A

公开(公告)日：1999-08-06

申请号：JP28902098

申请日：1998-10-12

Applicant: IBM

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

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

Abstract: PROBLEM TO BE SOLVED: To reduce the gap between magnetic shields to obtain a high surface density. SOLUTION: The magnetic shield enables a head to detect each magnetic transition from a magnetic recording medium without interference of adjacent transitions and functions as an electric lead which connects the head to a detection circuit. Conductive spacer layer 102 and 104 are arranged above and below an MTJ(magnetic tunnel junction) element to connect the MTJ element to the shield. The thickness of spacer layere 102 and 104 are selected so as to optimize the gap between shields. This thickness is a parameter which controls the linear resolution of data read from the magnetic recording medium. If the gap between shields is narrow, each shield has a pedestal area for the purpose of reducing a possibility of electric short-circuit between shields, and the MTJ element can be arranged between these two pedestals. In this case, the gap between shields on the outside of pedestals is larger than the inside of pedestal areas.

公开(公告)号：JPH11213349A

公开(公告)日：1999-08-06

申请号：JP28899998

申请日：1998-10-12

Applicant: IBM

Inventor： FONTANA JR ROBERT E ,  PARKIN STUART STEPHEN PAPWORTH ,  TSANG CHING HWA

IPC: G11B5/39 ,  G11B5/40

Abstract: PROBLEM TO BE SOLVED: To provide an MTJ(magnetic tunnel junction) MR(magneto-resistance) read head free from problems accompanying the existence of an edge part of an exposed MTJ layer on a detection surface. SOLUTION: The MTJ magneto-resistance read head for magnetic recording system is provided with an MTJ detection or free ferromagnetic layer 132 functioning as a magnetic flux guide which directs a magnetic flux from a magnetic recording medium to a tunnel junction. An MTJ fixed ferromagnetic layer 118 has a front edge part retreated from the detection surface of the head. The fixed ferromagnetic layer and the free ferromagnetic layer are brought into contact with opposite faces of an MTJ tunnel barrier layer 120, but the free ferromagnetic layer is extended beyond the rear edge part of one of the tunnel barrier layer and the fixed ferromagnetic layer which has the rear edge part nearer to the detection surface. The direction of magnetization of the fixed ferromagnetic layer is desirably fixed in the direction of an arrow 119 approximately perpendicular to the detection surface, namely, the magnetic recording medium by surface exchange coupling with an antiferromagnetic layer.

公开(公告)号：JPH11213350A

公开(公告)日：1999-08-06

申请号：JP28901398

申请日：1998-10-12

Applicant: IBM

Inventor： FONTANA JR ROBERT E ,  PARKIN STUART STEPHEN PAPWORTH ,  TSANG CHING HWA ,  WILLIAMS MASON LAMAR

IPC: G11B5/39 ,  G11B5/33

Abstract: PROBLEM TO BE SOLVED: To provide a magnetic tunnel junction magneto-resistance reading head for magnetic recording system which gives a large output signal. SOLUTION: The magneto-resistance read head is provided with an MTJ detection or free ferromagnetic layer 132 functioning as a magnetic flux guide which directs a magnetic flux from a magnetic recording medium to a tunnel junction 100, and an MTJ fixed ferromagnetic layer 118 and an MTJ tunnel barrier layer 120 are provided with front edge parts 206 and 210 which are approximately level with the detection surface of the head, and the fixed ferromagnetic layer 118 and the free ferromagnetic layer 132 are brought into contact with opposite faced of the MTJ tunnel barrier layer 120, and the free ferromagnetic layer 132 is extended beyond the rear edge part of one of the free ferromagnetic layer 132 and the tunnel barrier layer 118 which has the rear edge part 208 or 212 nearer to the detection surface, and it is secured that the magnetic flux is non-zero in the tunnel junction area. The direction of magnetization of the fixed ferromagnetic layer 118 is fixed in the direction perpendicular to the detection surface by surface exchange coupling with an antiferromagnetic layer 116. The direction of magnetization of the free ferromagnetic layer 132 is made parallel with the surface of a medium when an applied magnetic field is zero, and it is freely rotated when an applied magnetic field exists.

公开(公告)号：JP2002304711A

公开(公告)日：2002-10-18

申请号：JP2001389357

申请日：2001-12-21

Applicant: IBM

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

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

Abstract: PROBLEM TO BE SOLVED: To provide an MR read head having an MTJ device formed to be sufficiently thin for attaining the high surface density by reducing the space between magnetic shields. SOLUTION: As to the magnetic tunnel junction MTJ device 100, the magneto-resistive(MR) read head has the MTJ device 100 located between two spaced-apart magnetic shields S1, S2. The magnetic shields function also as electrical leads for connecting the head to a detection circuit. Conductive spacer layers 102, 104 are located at the top and bottom of the MTJ device 100 to connect the MTJ device 100 to the shields. The thickness of the spacer layer is selected to optimize the spacing between the shields. Each of the shields has the pedestal region for reducing the electric short-circuit between the shields in the case the space between the shields is too small, and the MTJ device 100 is located between these two pedestals.

公开(公告)号：JPH11353621A

公开(公告)日：1999-12-24

申请号：JP14418599

申请日：1999-05-25

Applicant: IBM

Inventor： FONTANA JR ROBERT E ,  PARKIN STUART STEPHEN PAPWORTH ,  CHIN FA TSUAN

IPC: G01R33/06 ,  G11B5/39

Abstract: PROBLEM TO BE SOLVED: To prevent the shunting of the sense current to a bias ferromagnetic layer and to optimize a device by determining electric resistance to current flowing perpendicularly in respective layers in a stack by the relative directions of the magnetic moments of a stationary ferromagnetic layer and detecting ferromagnetic layer when electric leads are connected to a sensing circuit. SOLUTION: The bias magnetic field in the transverse direction to a magnetic tunnel junction device (MTJ) is obtd. by the ferromagnetic bias layer 320 having a longitudinally bias region 322 near the right and left edges 180 of a detecting layer and a transverse bias region 324 along a rear surface edge 190 apart from an air bearing surface (ABS) surface. The front edge of an MTJ sensor 100 is directly arranged on the ABS or is retreated from the ABS to introduce magnetic fluxes to the retreated front edge of the sensor by using a magnetic flux guide. The transverse bias magnetic field of an adequate quantity is made possible by using an additional bias region 324 at the rear surface edge 190.

公开(公告)号：JPH104227A

公开(公告)日：1998-01-06

申请号：JP5877797

申请日：1997-03-13

Applicant: IBM

Inventor： GALLAGHER WILLIAM JOSEPH ,  PARKIN STUART STEPHEN PAPWORTH ,  SLONCZEWSKI JOHN CASIMIR ,  JONATHAN ZANHON SAN

IPC: G01R33/06 ,  G01R33/09 ,  G11B5/39 ,  G11C11/14 ,  G11C11/15 ,  G11C11/16 ,  H01L21/8246 ,  H01L27/105 ,  H01L27/22 ,  H01L43/08

Abstract: PROBLEM TO BE SOLVED: To control magnetoresistance response to a magnetic signal by a method wherein a constrained ferromagnetic layer, having a side part circumfer ence which is not extended over the side part circumference of an insulating tunnel layer, is retained within the another spaced plane surface without overlap ping with an insulating tunnel layer. SOLUTION: Write in an MJT is attained by allowing a current to flow through the upper and lower electrode wiring layers on the memory cell application of a magnetic tunnel junction MTJ element. When a sufficiently large current is allowed to flow through the above-mentioned lines, the magnetization direction of a free ferromagnetic layer 32 is rotated in reverse parallel from parallel to the magnetization direction of a constrained ferromagnetic layer 18 by the coupled magnetic field formed in the vicinity of a free ferromagnetic layer 32. Current level is selected in such a manner that the coupling magnetic field to be formed exceeds the switching field of the free ferromagnetic layer. The magnetic field formed by a coupling write-in current is selected smaller than the magnetic field required for rotation of the magnetization direction of the constrained ferromagnetic layer.

公开(公告)号：JP2005123617A

公开(公告)日：2005-05-12

申请号：JP2004297247

申请日：2004-10-12

Applicant: Internatl Business Mach Corp ,  インターナショナル・ビジネス・マシーンズ・コーポレーションInternational Business Maschines Corporation

Inventor： PARKIN STUART STEPHEN PAPWORTH

IPC: G11C11/15 ,  G11C11/14 ,  G11C19/08 ,  H01L21/8246 ,  H01L27/105 ,  H01L43/08

CPC classification number: G11C19/0808 ,  B82Y10/00 ,  G11C11/14

Abstract: PROBLEM TO BE SOLVED: To generate a very strong magnetic field by switching of memory elements, without being affected by the shape and size of memory elements, thereby satisfying the requirement of an MRAM structure, which enables to produce a small magnetic element having sufficient magnetic stability, to cope with the temperature fluctuations. SOLUTION: For the purpose of writing data on an unpatterned magnetic film, digital information is stored on the unpatterned magnetic film utilizing the intrinsic and inherent properties of magnetic wall in ferromagnetic material. Making use of MTJ, the data are read from this unpatterned magnetic field. In order to achieve sufficient stability with respect to temperature, magnetic field needed for changing the direction of these magnetic areas can be strengthened far stronger that the one brought about by current flow in wire. Such a strong magnetic field can be realized, using wall leak magnetic field generated on the border of two magnetic walls. Writing on these magnetic areas is performed by using the wall leak magnetic field in the adjoining magnetic wire. These wires are brought near a magnetic storage layer, where writing in a magnetic storage area should be performed. COPYRIGHT: (C)2005,JPO&NCIPI

Abstract translation: 要解决的问题：为了通过存储元件的切换来产生非常强的磁场，而不受存储元件的形状和尺寸的影响，从而满足MRAM结构的要求，其能够产生小的磁性元件 具有足够的磁稳定性，以应对温度波动。

解决方案：为了在无图案磁性膜上写入数据，利用铁磁材料中磁性壁的固有和固有特性，将数字信息存储在未图案化的磁性膜上。 利用MTJ，从无图形磁场读取数据。 为了获得相对于温度的足够的稳定性，可以加强改变这些磁性区域的方向所需的磁场，使得由电流中的电流引起的磁场强度更强。 可以实现这样强大的磁场，使用在两个磁性壁的边界上产生的壁泄漏磁场。 通过使用邻接的电磁线中的壁泄漏磁场，对这些磁场进行写入。 这些电线被带到磁存储层附近，其中应该在磁存储区域中进行写入。 版权所有（C）2005，JPO＆NCIPI

公开(公告)号：JPH11161919A

公开(公告)日：1999-06-18

申请号：JP25792198

申请日：1998-09-11

Applicant: IBM

Inventor： PARKIN STUART STEPHEN PAPWORTH

IPC: G11B5/39 ,  G11C11/15 ,  G11C11/16 ,  H01F10/32 ,  H01L43/08

Abstract: PROBLEM TO BE SOLVED: To provide MTJ elements which are reduced in the magnetic moment of the nets of ferromagnetic layers so as to controllably decrease the magnetostatic interactions between the ferromagnetic layers within the single element or between the MTJ elements without much complication in the formation of the MTJ elements. SOLUTION: The improved magnetic tunnel junction (MTJ element) useful within the magnetic record reading head or magnetic memory storage cell consists of the two ferromagnetic layers, i.e., the 'hard' or 'stationary' ferromagnetic layer 118 and the detection or 'free' ferromagnetic layer 132, which are separated by a thin insulation tunnel layer 120. Each of the respective ferromagnetic layers is multiple layers consisting of two thinner ferromagnetic films which are antiferromagnetically bonded across the thin antiferromagnetic bond film 116 to each other. The antiferromagnetic bond film is so selected with respect to its material compsn. and thickness that the magnetic moments 133 of the two ferromagnetic films holding itself in the absence of external magnetic first are aligned antiparallel with each other.

公开(公告)号：JPH10190090A

公开(公告)日：1998-07-21

申请号：JP27623897

申请日：1997-10-08

Applicant: IBM

Inventor： PARKIN STUART STEPHEN PAPWORTH

IPC: G01R33/06 ,  G01R33/09 ,  G11B5/39 ,  G11C11/15 ,  G11C11/16 ,  H01F10/08 ,  H01F10/16 ,  H01F10/32 ,  H01L21/8246 ,  H01L27/105 ,  H01L43/00 ,  H01L43/08

Abstract: PROBLEM TO BE SOLVED: To optimize controllability in a central magnetic field region of a response curve by positioning an insulation tunnel layer between a fixed ferromagnetic layer and a free ferromagnetic layer on a board and positioning a non-ferromagnetic surface phase layer between an insulation tunnel layer and one of ferromagnetic layers. SOLUTION: An Al2 O3 tunnel/barrier layer 20 which can make a tunnel current flow in an almost vertical direction is provided between a fixed ferromagnetic layer 18 which is above a board 9 and is fixed in a proper direction when application magnetic field exists and a free ferromagnetic layer 32 wherein magnetization is freely rotative. Furthermore, a non-ferromagnetic surface phase layer 31 which weakens magnetic combination between the fixed ferromagnetic layer 18 and the free ferromagnetic layer 32 is inserted between the barrier layer 20 and the free ferromagnetic layer 32. When applied magnetic field is in a favorable range, the fixed ferromagnetic layer 18 contains a high coercive force material (ternary alloy such as CoPtCr) to be pinned by proper magnetic anisotropy and have a remaining moment of magnetic field close to zero magnetic field.

公开(公告)号：SG82614A1

公开(公告)日：2001-08-21

申请号：SG1999002429

申请日：1999-05-13

Applicant: IBM

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

IPC: G01R33/06 ,  G11B5/39

Abstract: A magnetic tunnel junction magnetoresistive read head has one fixed ferromagnetic layer and one generally rectangularly shaped sensing ferromagnetic layer on opposite sides of the tunnel barrier layer, and a biasing ferromagnetic layer located around the side edges and back edges of the sensing ferromagnetic layer. An electrically insulating layer separates the biasing layer from the edges of the sensing layer. The biasing layer is a continuous boundary biasing layer that has side regions and a back region to surround the three edges of the sensing layer. When the biasing layer is a single layer with contiguous side and back regions its magnetic moment can be selected to make an angle with the long edges of the sensing layer. In this manner the biasing layer provides both a transverse bias field to compensate for transverse ferromagnetic coupling and magnetostatic coupling fields acting on the sensing layer to thus provide for a linear response of the head and a longitudinal bias field to stabilize the head. The biasing layer may also be formed with discrete side regions and a back region. The discrete side regions may have a magnetic moment oriented in a different direction from the moment of the back region in order to provide the correct combination of transverse and longitudinal bias fields.