Hitachi Global Storage Technologies Netherlands B.v.

Hgst Netherlands, B.v.

International Business Machines Corporation

Western Digital Technologies, Inc.

Hitachi Global Storage Technologies

Stefan Maat

Matthew Joseph Carey

Jeffrey Childress

Eric Edward Fullerton

Bruce Alvin Gurney

Alexander Michael Zeltser

Neil Smith

Robert Fontana

Ernesto Esteban Marinero

James Mac Freitag

Jan-Ulrich Thiele

Philip M Rice

Amitava Chattopadhyay

Thai Le

Zheng Gao

David John Seagle

Wen-Chien David Hsiao

Jordan Asher Katine

Howard Gordon Zolla

Ning Shi

James Lamar Nix

Liesl Folks

Shekar B Chandrashekariaih

Hardayal Singh Gill

Mustafa Pinarbasi

Quang Le

Cherngye Hwang

Daniele Mauri

Kuok San Ho

Bruce Alexander Wilson

Luiz M Franca-Neto

Yi Zheng

Simon H Liao

Hal Jervis Rosen

Bernhard E Knigge

Yimin Hsu

Petrus Antonius Van Der Heijden

Stuart Stephen Papworth Parkin

Ying Hong

Klaas Berend Klaassen

Satoru Araki

James Terrence Olson

Ian Robson McFadyen

Marie-Claire Cyrille

Thomas Dudley Boone, Jr

Prakash Kasiraj

Honglin Zhu

Kentaro Takano

Xiaozhong Dang

Wen-yaung Lee

Guangli Liu

Hicham Moulay Sougrati

Hieu Lam

Arley Cleveland Marley

Shuxia Wang

Yongho Ju

Thomas Robert Berthold

Masaya Nishioka

A two-dimensional magnetic recording (TDMR) read head with an antiferromagnetic (AFM) layer recessed behind a center shield. The TDMR read head comprises a first read sensor and a center shield over the first read sensor, wherein the center shield has a first thickness at an air-bearing surface (ABS) and a second thickness at a back surface, the first thickness being greater than the second thickness. A ferromagnetic layer is disposed over a portion of the center shield, wherein the ferromagnetic layer is recessed from the ABS. The TDMR read head also includes an antiferromagnetic layer over the ferromagnetic layer and a second read sensor over the antiferromagnetic layer. By recessing the AFM layer away from the ABS, the down-track spacing between read sensors is reduced, thereby improving TDMR read head performance.

Two-dimensional magnetic recording device with center shield stabilized by recessed AFM layer

The embodiments of the present invention relate to a method for forming a magnetic read head with pinned layers extending to the ABS of the read head and magnetically coupled with an antiferromagnetic layer that is recessed in relation to the ABS of the read head. Portions of the antiferromagnetic layer and a magnetic layer that are extending to the ABS are removed, exposing a shield. A shielding material is formed on the exposed shield and a seed layer is formed on the shield and on or over a portion of the remaining antiferromagnetic layer. A pinned layer structure is formed on the seed layer and the magnetic layer.

Recessed IRMN reader process

A two-dimensional magnetic recording (TDMR) read head has upper and lower read sensors wherein the lower read sensor has its magnetization biased by side shields of soft magnetic material. The center shield between the lower and upper sensors may be an antiparallel structure (APS) with two ferromagnetic layers separated by an antiparallel coupling (APC) layer. The center shield has a central region and two side regions, but there is no antiferromagnetic (AF) layer in the central region. Instead the two side regions of the upper ferromagnetic layer in the APS are pinned by AF tab layers that are electrically isolated from the upper sensor. The upper ferromagnetic layer and the APC layer in the APS may also be located only in the side regions. The thickness of the center shield can thus be made thinner, which reduces the free layer to free layer spacing.

Current-perpendicular-to-the-plane (CPP) magnetoresistive (MR) sensor structure with multiple stacked sensors and improved center shield

A two-dimensional magnetic recording (TDMR) read head structure has the lower read sensor free layer magnetization biased by side shields of soft magnetic material. A center shield between the lower and upper sensors is an antiparallel coupled magnetic structure, i.e., first and second ferromagnetic layers separated by an antiparallel coupling (APC) layer. The first ferromagnetic layer is ferromagnetically exchange coupled to the side shields of the lower sensor to stabilize the magnetization of the lower sensor's free layer. The first ferromagnetic layer of the center shield is a multilayer of a lower NiFe layer and an upper CoFeB alloy layer inserted below the APC layer. The CoFeB alloy insertion layer increases the antiparallel coupling of the first and second ferromagnetic layers of the center shield after two orthogonal anneals so that the magnetization of the first ferromagnetic layer is aligned parallel to the air-bearing surface (ABS) of the TDMR structure.

Current-perpendicular-to-the-plane (CPP) magnetoresistive (MR) sensor structure with multiple stacked sensors and center shield with CoFeB insertion layer

A perpendicular magnetic recording write head has a main pole that is typically CoFe electroplated into a generally trapezoidal shaped alumina trench. A metallic side gap layer is deposited into the alumina trench to adjust the trench width to the desired main pole dimension. A nonmagnetic metallic amorphous underlayer, preferably an amorphous NiTa alloy or an amorphous NiNb alloy, is then deposited on the side gap layer. A pole seed layer, such as a NiCr/CoFe bilayer, is deposited into the trench onto the metallic amorphous underlayer prior to electroplating the CoFe main pole. The metallic amorphous underlayer serves to reset the growth between the side gap layer and the NiCr/CoFe pole seed layer. The metallic amorphous underlayer does not insulate the electroplating CoFe layer from the metallic side gap layer, which allows for better current conduction normal to the layers, resulting in a main pole with improved magnetic properties.

Perpendicular magnetic recording write head with main pole formed on a metallic amorphous underlayer

A current-perpendicular-to-the-plane (CPP) magnetoresistive (MR) sensor has both side shields and an antiparallel structure (APS) top shield. The APS top shield is an antiferromagnetically exchange-coupled top shield that includes an antiparallel (AP) coupled structure and an antiferromagnetic (AF) layer which permits the use of the desired NiFe(x is between 15 and 25 atomic percent) material for the side shields. The APS top shield includes lower and upper ferromagnetic layers with respective antiparallel magnetizations. The antiparallel coupling structure between the two ferromagnetic layers consists of the antiparallel coupling (APC) film, which is typically Ru, Ir or Cr, and one and only one interface film of Co or CoFe. The APS top shield with one and only one Co or CoFe interface film enables the material of the side shields to be formed of the preferred NiFe(x is between 15 and 25 atomic percent) material without over-stabilization of the free layer.

Current-perpendicular-to-the-plane (CPP) magnetoresistive (MR) sensor with side shields and an antiparallel structure top shield

A magnetic scissor type magnetic read head having magnetic side shielding for reduced effective track width and having side biasing for improved stability. The read head includes first and magnetic side shields that each include first and second magnetic layers and an anti-parallel exchange coupling layer sandwiched there-between. The magnetic layers of the side shields are anti-parallel coupled with one another such that one of the magnetic layers has its magnetization oriented in a first direction parallel with the air bearing surface and the second magnetic layer has its magnetization oriented in a second direction that is opposite to the first direction and also parallel with the air bearing surface. These magnetizations of the first and second magnetic layers provide a bias field that stabilizes the magnetization of the free magnetic layers of the sensor stack to prevent flipping of the magnetizations of these layers.

Scissor magnetic read head with wrap-around magnetic shield

A hard magnet biasing structure for a CPP-GMR or CPP-TMR read head for a magnetic recording disk drive is located between the two sensor shields and abutting the side edges of the sensor free layer. The biasing structure includes a crystalline MgO insulating layer on the lower shield and the side edges of the free layer, a seed layer of either Ir or Ru on and in contact with the MgO layer, a layer of at least partially chemically-ordered ferromagnetic FePt alloy hard bias layer on the seed layer, and a capping layer on the FePt alloy hard bias layer. The MgO layer may be a single layer on and in contact with the side edges of the free layer, or an upper layer on and in contact with a base insulating layer selected from an aluminum oxide, a tantalum oxide, a titanium oxide, and a silicon nitride.

Current-perpendicular-to-the-plane (CPP) magnetoresistive (MR) sensor with hard magnet biasing structure having a MgO insulating layer

A magnetoresistive sensor that has a free layer with a face centered cubic, 100 crystal orientation formed on an underlayer structure that has been deposited in the presence of nitrogen. The free layer can be constructed of CoFe, Co(MnFe)X (where 0&#x2266;y&#x2266;1 and X is Si, Ge, Sn, Al, Ga, or a combination thereof), CoFeX (where X is Si, Ge, Sn, Al, Ga, or a combination thereof). The under-layer can include a layer of Ta, a Cu layer formed over the layer of Ta and deposited using a process gas comprising about 20 percent nitrogen and a layer of Ag deposited over the layer of Cu and deposited using a process gas comprising about 50 to 100 percent nitrogen.

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A current-perpendicular-to-the-plane magnetoresistive sensor structure includes at least an improved top shield structure and optionally also a similar bottom shield structure. The top shield structure includes an antiparallel structure (APS) of two ferromagnetic films and a nonmagnetic antiparallel coupling (APC) film between them. The APC film induces antiferromagnetic (AF) coupling between the two ferromagnetic films so that they have their respective magnetizations oriented antiparallel. An important aspect of the APS is that there is no antiferromagnetic layer adjacent the upper ferromagnetic film, so that the upper ferromagnetic film does not have its magnetization pinned by an antiferromagnetic layer. An electroplated shield layer is formed above the APS. A nonmagnetic decoupling layer is located between the APS and the electroplated shield layer to prevent domain wall movement in the electroplated shield from transferring to the ferromagnetic layers in the APS and thus possibly induce noise in the sensor.

Current-perpendicular-to-the-plane (CPP) magnetoresistive (MR) sensor having a top shield with an antiparallel structure

A current-perpendicular-to-the-plane magnetoresistive sensor has an exchange-coupled side shield structure on each of two side regions of the sensor and an exchange-coupled top shield structure on the sensor and the two exchange-coupled side shield structures. Each exchange-coupled structure comprises an antiferromagnetic layer and a shield of soft magnetically permeable material exchange-coupled with the antiferromagnetic layer. Each side shield and the top shield has its magnetization oriented generally parallel to the sensor front edge and generally parallel to the plane of the sensor's free ferromagnetic layer. The shields in each exchange-coupled side shield structure and the exchange-coupled top shield structure may be an antiparallel coupled structure of two magnetically permeable films separated by a nonmagnetic coupling film.

Current-perpendicular-to-the-plane (CPP) magnetoresistive (MR) sensor with exchange-coupled side shield structure

A magnetic field sensing system with a current-perpendicular-to-the-plane (CPP) sensor, like that used for giant magnetoresistive (GMR) and tunneling magnetoresistive (TMR) spin-valve (SV) sensors, operates in a mode different from conventional GMR-SV and TMR-SV systems. An alternating-current (AC) source operates at a fixed selected frequency and directs AC perpendicularly through the layers of the CPP sensor, with the AC amplitude being high enough to deliberately induce a spin-torque in the CPP sensor's free layer. The AC-induced spin-torque at the selected frequency causes oscillations in the magnetization of the free layer that give rise to a DC voltage signal V. Vis a direct result of only the oscillations induced in the free layer. The value of Vwill change in response to the magnitude of the external magnetic field being sensed and as the free layer is driven in and out of resonance with the AC.

Magnetic field sensing system using spin-torque diode effect

A current-perpendicular-to-the-plane (CPP) magnetoresistive (MR) sensor has an improved seed layer structure for the ferromagnetic hard (high coercivity) bias layer that is used to longitudinally bias the sensor's free ferromagnetic layer. The seed layer structure is a trilayer consisting of a first seed layer of tantalum (Ta), a second seed layer of one or both titanium (Ti) and Ti-oxide on and in contact with the Ta layer, and a third seed layer of tungsten (W) on and in contact with the second seed layer.

Current-perpendicular-to-the-plane (CPP) magnetoresistive (MR) sensor with improved seed layer structure for hard bias layer

A tunneling magnetoresistance (TMR) device, like a TMR read head for a magnetic recording disk drive, has low magnetic damping, and thus low mag-noise, as a result of the addition of a ferromagnetic backing layer to the ferromagnetic free layer. The backing layer is a material with a low Gilbert damping constant or parameter &#x3b1;, the well-known dimensionless coefficient in the Landau-Lifshitz-Gilbert equation. The backing layer may have a thickness such that it contributes up to two-thirds of the total moment/area of the combined free layer and backing layer. The backing layer may be formed of a material having a composition selected from (CoFe)X, (CoMn)Xand (CoFeMn)X, where X is selected from Ge, Al and Si, and (CoFe)Al, where y is in a range that results in a low damping constant for the material.

Tunneling magnetoresistive (TMR) read head with low magnetic noise

A current-perpendicular-to-the-plane spin-valve (CPP-SV) magnetoresistive sensor has a ferromagnetic alloy comprising Co, Fe and Ge in the sensor's free layer and/or pinned layer and a spacer layer of Ag, Cu or a AgCu alloy between the free and pinned layers. The sensor may be a simple pinned structure, in which case the pinned layer may be formed of the CoFeGe ferromagnetic alloy. Alternatively, the sensor may have an AP-pinned layer structure, in which case the AP2layer may be formed of the CoFeGe ferromagnetic alloy. The Ge-containing alloy comprises Co, Fe and Ge, wherein Ge is present in the alloy in an amount between about 20 and 40 atomic percent, and wherein the ratio of Co to Fe in the alloy is between about 0.8 and 1.2.

Current-perpendicular-to-the-plane (CPP) magnetoresistive sensor with CoFeGe ferromagnetic layers and Ag or AgCu spacer layer

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San Jose, CA, United States of America

Stefan Maat