International Business Machines Corporation

Hitachi Global Storage Technologies Netherlands B.v.

Magic Technologies, Inc.

Other

David Eugene Heim

Hardayal Singh Gill

Kim Yang Lee

Tsann Lin

Hugo Alberto Santini

Jih-Shiuan Luo

Mustafa Pinarbasi

Po-Kang Wang

Bruce Alvin Gurney

Tai Min

Virgil S Speriosu

Dennis R Wilhoit

Haralambos Lefakis

Vladimir Nikitin

David John Seagle

Daniele Mauri

Kuok San Ho

James Mac Freitag

Richard Hsiao

Neil Leslie Robertson

Ching Hwa Tsang

Thomas Young Chang

Wipul Jayasekara

Chun-Ming Wang

Jyh-Shuey Jerry Lo

Kevin Robert Coffey

Robert Beach

Stuart Stephen Parkin

Edward Hinpong Lee

Michael J Armstrong

William C Cain

Wai-Ming Johnson Kan

Chyu Jiuh Torng

Mason L Williams, Iii

Omar U Need, Iii

A narrow track-width magnetoresistive sensor by defining a trench formed between first and second hard bias layers and depositing the sensor into the trench. The sensor can include a sensor stack sandwiched between first and second electrically conductive lead layers. First and second electrically insulating side walls are formed at either side of the sensor stack. First and second hard bias layers extend from the sides of the sensor stack, being separated from the sensor stack by the first and second electrically insulating side walls. First and second physically hard insulation layers are provided over each of the hard bias layers.

Magnetic sensor having a physically hard insulation layer over a magnetic bias structure

A cladding structure for a conductive line used to switch a free layer in a MTJ is disclosed and includes two cladding sidewalls on two sides of the conductive line, a top cladding portion on a side of the conductive line facing away from the MTJ, and a highly conductive, non-magnetic spacing control layer formed between the MTJ and conductive line. The spacing control layer has a thickness of 0.02 to 0.12 microns to maintain the distance separating free layer and conductive line between 0.03 and 0.15 microns. The spacing control layer is aligned parallel to the conductive line and contacts a plurality of MTJ elements in a row of MRAM cells. Half-select error problems are avoided while maintaining high write efficiency. A spacing control layer may be formed between a word line and a bottom electrode in a top pinned layer or dual pinned layer configuration.

Fabrication methods of partial cladded write line to enhance write margin for magnetic random access memory

The incidence of half-select errors during MRAM programming has been significantly reduced by giving the free layer a shape that approximates an X so that, when the free layer switches, the magnetization in the arms of the X guides the magnetization in the central section (the X's intersection area) causing it to rotate towards the hard axis in two opposing directions. This raises the free layer's switching energy barrier, thereby reducing half-select errors.

MRAM with cross-tie magnetization configuration

A lead overlay design of a magnetic sensor is described with sensor and free layer dimensions such that the free layer is stabilized by the large demagnetization field due to the shape anisotropy. In one embodiment the giant magnetoresistive (GMR) effect under the leads is destroyed by removing the antiferromagnetic (AFM) and pinned layers above the free layer. The overlaid lead pads are deposited on the exposed spacer layer at the sides of the mask that defines the active region. In other embodiment a layer of electrically insulating material is deposited over the sensor to encapsulate it and thereby insulate it from contact with the hardbias structures. Various embodiments with self-aligned leads are also described. In a variation of the encapsulation embodiment, the insulating material is also deposited under the lead pads so the electrical current is channeled through the active region of the sensor and sidewall deposited lead pads.

Magnetic sensor with extended free layer and overlaid leads

In a tunnel magnetoresistive (TMR) device, free sublayers are separated by an intermediate spacer layer that serves to ensure a uniform circumferential magnetization in the free stack, counterbalancing orange-peel coupling by antiferromagnetic exchange coupling. Thus, a CPP MR device may have a seed stack, a pinned stack on the seed stack, and a tunnel barrier on the pinned stack. A free stack can be on the tunnel barrier, and the free stack can include structure for promoting uniform circumferential magnetization in the free stack.

Tunnel MR head with closed-edge laminated free layer

A method is disclosed for fabricating a read sensor for a magnetic head for a hard disk drive having a read sensor stack and two lateral stacks. The method of fabrication includes forming lateral stacks on a gap layer, surrounding a groove to form a template. The read sensor stack is then formed in the groove, which defines the lateral dimensions of the read sensor stack, and lead layers are then formed on the lateral stacks. Also disclosed is a read head for a disk drive having a sensor stack defined by pre-established lateral stacks, and a disk drive having the read head.

Method for fabricating a magnetic head having a sensor stack and two lateral stack

A method of constructing a small trackwidth magnetorsesistive sensor by defining a trench between first and second hard bias layers and depositing the sensor into the trench.

Topographically defined thin film CPP read head fabrication

In one illustrative example, a spin valve sensor includes a free layer structure; an anti-parallel (AP) pinned layer structure which includes at least a first AP pinned layer; and a non-magnetic electrically conductive spacer layer formed between the free layer structure and the AP pinned layer structure. First and second antiferromagnetic (AFM) pinning layer structures for magnetically pinning the first AP pinned layer are formed in end regions but are absent from its central region. Edges of each AFM pinning layer structure may be separated by a distance Dfrom the sensor edges. The first AP pinned layer is formed in both the central region and the end regions so as to be in contact with the first and second AFM pinning layer structures. Advantageously, adequate pinning properties are exhibited in a sensor which provides the benefits of a self-pinned sensor (e.g. a reduced sensor profile in the central region).

Spin valve sensor having antiferromagnetic (AFM) pinning layer structures formed in the end regions

A magnetoresistive sensor has bias magnets with substantially vertical end walls. The offset between the bias magnets and the free layer is optimized by adjusting the thickness of a spacer layer. A disk drive has a read element including a magnetoresistive sensor with optimized bias magnets having substantially vertical end walls.

Magnetoresistive sensor having bias magnets with steep endwalls

A write head is provided that has an 'I' shaped pole tip structure. Flux leakage between bottom corners of a top horizontal component to a bottom horizontal component of the 'I' shaped pole tip structure is obviated by rounding or tapering the side edges of the top horizontal component as it recesses into the head from the ABS. The angle taken by each recessed side edge with respect to the ABS edge is less than 90.degree. so that flux concentrations at the corners are minimized and flux leakage from these corners to the bottom horizontal component is substantially eliminated. In another embodiment of the invention the top horizontal component is configured with a necked down portion between front and rear portions for minimizing flux saturation of other pole tip components.

Contoured pole tip structures for minimizing side track erasure

The present invention uncouples the dependence between the zero throat height and the flare point of a write head by recessing the first insulation layer within the first pole piece layer. The first pole piece layer and the first insulation layer have planar surfaces which preferably lie in a common plane, the zero throat height being defined at the point where the planar surface of the first pole piece layer first meets the planar surface of the first insulation layer within the head. It is also at this point that the first and second pole piece layers separate from one another. Accordingly, the zero throat height can be accurately placed relative to the stripe height of a magneto-resistive (MR) sensor. Further, when a photoresist layer is spun onto the partially completed head for the construction of the pole tip of the second pole piece light directed into the photoresist layer for photo-imaging the pole tip does not reflect into the photoresist layer adjacent the pole tip. Accordingly, there is substantially no reflective notching of the photoresist layer because of the flatness of the surfaces of the first pole piece layer and the first insulation layer thereby permitting construction of a well defined second pole tip.

Method of making thin film induction recording head having an inset

A method for making a merged thin film read/write head, where the first pole piece includes a pedestal or pole tip portion that extends up from the first pole piece layer, uses electroplating to form the gap so that the gap layer does not have to be removed later. After the first pole piece is deposited, the coil insulation structure is built over the first pole piece. Afterwards an electrically conductive seed layer of the same ferromagnetic material as the first pole piece is formed over the wafer to provide an electrically conductive path for subsequent electroplating. After the seed layer deposition, a photoresist pattern is then formed to define the shape of the second pole piece. Nonmagnetic nickel-phosphorous is then electroplated onto the seed layer in the region not covered by the photoresist pattern to form the gap layer. The second ferromagnetic layer is then electroplated onto the gap layer to define the shape of the second pole piece. The thickness of the second pole piece layer is deliberately made thicker than the desired final thickness because the second pole piece layer is used as a mask for subsequent ion beam milling to form the notched pole tip element of the first pole piece. The photoresist is removed and ion beam milling performed to remove the seed layer and a portion of the first pole piece layer to define the pedestal pole tip element of the first pole piece. The ion beam milling does not have to remove the gap layer because the electroplated gap has been defined by the photoresist pattern to have the desired trackwidth.

Method for making a thin film inductive write head having a pedestal

Thin film induction recording head having an inset first insulation

A magnetic storage system in which a magnetoresistive (MR) transducer utilizes a high coercivity magnetic material to produce a bias field for achieving higher signal output with low currents for narrow track width applications. Strips of high coercivity magnetic material contiguously contact opposite track-overlying edges of an MR layer. Each strip has a horizontal component of magnetization times its thickness that is at least equal to a horizontal component of magnetization of the MR layer times its thickness before the MR layer is biased by the strips, and each strip has its magnetization direction canted at an angle .phi. from its horizontal component. The MR layer is asymmetrically positioned between spaced magnetic shields and the MR layer is separated by a conductive nonmagnetic spacer layer from a shunt layer. Alternatively, the shunt layer is replaced by a reduced thickness soft film layer and the MR layer is centered between the shields and the strips also contiguously contact track overlying edges of the soft film layer.

Magnetic storage system with canted hardbias magnetoresistive head

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Redwood City, CA, United States of America

David Eugene Heim