Hitachi Global Storage Technologies Netherlands B.v.

International Business Machines Corporation

Agency for Science, Technology and Research

Hgst Netherlands, B.v.

Hitachi Global Storage Technologies

Wen-yaung Lee

Brian Rodrick York

Daniele Mauri

Jinshan Li

Alexander Michael Zeltser

Tsann Lin

Dulip Ajantha Welipitiya

Thomas E Shatz

Koichi Nishioka

Yasunari Tajima

Danielle Mauri

Hardayal Singh Gill

Mustafa Pinarbasi

Wen-Chien David Hsiao

Stefan Maat

Jerome Michael Eldridge

Eric Edward Fullerton

Howard Gordon Zolla

Mary Frances Doerner

Marie-Claire Cyrille

Prakash Kasiraj

Ciaran Avram Fox

Geraldine C Schwartz

Yihong Wu

Yongho Ju

Chang Man Park

Kebin Li

Methods and apparatus provide magnetoresistance sensors. A tunneling magnetoresistance (TMR) sensor may include configurations that are arranged as a top TMR stack. One of two antiparallel layers of pinned layers within the TMR stack may be subdivided by a spacer layer. Tantalum may form the spacer layer that is inserted in a reference layer, which is one of the pinned layers and is located between a barrier layer and an antiparallel coupling layer that enables antiparallel coupling between the reference layer and a keeper layer of the pinned layers. The barrier layer deposited on a free layer of the TMR stacks separates the pinned layers from the free layer such that TMR effects are detectable with the sensors.

Magnetoresistive sensor with sub-layering of pinned layers

A magnetoresistive sensor having an antiparallel coupled pinned layer structure including an APlayer and an APlayer. The APlayer includes two ferromagnetic layers AP() and AP(), and a separation layer sandwiched therebetween. The AP() layer is significantly larger than the AP() layer, which results in strong pinning, while the separation layer provides increased TMR and reduced RA.

Magnetoresistive sensor with novel pinned layer structure

An anti-parallel pinned sensor is provided with a spacer that increases the anti-parallel coupling strength of the sensor. The anti-parallel pinned sensor is a GMR or TMR sensor having a pure ruthenium or ruthenium alloy spacer. The thickness of the spacer is less than 0.8 nm, preferably between 0.1 and 0.6 nm. The spacer is also annealed in a magnetic field that is 1.5 Tesla or higher, and preferably greater than 5 Tesla. This design yields unexpected results by more than tripling the pinning field over that of typical AP-pinned GMR and TMR sensors that utilize ruthenium spacers which are 0.8 nm thick and annealed in a relatively low magnetic field of approximately 1.3 Tesla.

Enhanced anti-parallel-pinned sensor using thin ruthenium spacer and high magnetic field annealing

A magnetic head of either CIP or CPP configuration is disclosed, having a read sensor with a strongly pinned ferromagnetic layer due to increased electronic exchange with the AFM layer. The read sensor includes a lower seed layer whose material is chosen from a group consisting of Ta, NiFeCr, NiFeCoCr, NiFe, Cu, Ta/NiFeCr, Ta/NiFeCr/NiFe, Ta/Ru and Ta/NiFeCoCr, and an upper seed layer where the upper seed layer material is chosen from a group consisting of Ru, Cu, NiFe, Cu(x)Au(1&#x2212;x)(x=0.22-0.5) alloys, Ru(x)Cr(1&#x2212;x)(x=0.1-0.5) alloys, NiFeCr and NiFeCoCr. An AFM layer is formed on the upper seed layer and a ferromagnetic pinned layer is formed on the AFM layer. The exchange coupling energy Jk between the AFM layer and pinned layers exceeds 1.3 erg/cm2. Also disclosed is a method of fabrication of a magnetic head including a read head sensor with a strongly pinned ferromagnetic layer due to increased electronic exchange.

Magnetic read head having increased electron exchange

A method for fabricating a magnetic head including a spin valve sensor having a sensor layer stack that includes a pinned magnetic layer, a spacer layer formed on the pinned magnetic layer, and a free magnetic layer formed on the spacer layer. In a preferred embodiment the spacer layer is comprised of CuO. The method includes the plasma smoothing of the upper surface of the pinned magnetic layer prior to depositing the spacer layer, and a preferred plasma gas is a mixture of argon and oxygen.

Method for fabricating a magnetic head including a read sensor

A magnetoresistive sensor having a Ta cap layer with nitrogen added in situ during deposition. The nitrogen in the cap layer can be formed by depositing a Ta cap layer in a sputter deposition chamber having a small amount of nitrogen in an Ar atmosphere. The resulting nitrogenated cap layer exhibits reduced specular scattering, which results in improved magnetic performance of the magnetoresistive sensor.

GMR sensor having a capping layer treated with nitrogen for increased magnetoresistance

A magnetic head and magnetic storage system containing such a head, the head including a free layer and a layer of metal oxide substantially epitaxially formed relative to the free layer. Preferably, the layer of metal oxide is a crystalline structure, and is of ZnO.

Epitaxial oxide cap layers for enhancing GMR performance

A magnetic head having a free layer and an antiparallel (AP) pinned layer structure spaced apart from the free layer. The AP pinned layer structure includes at least two pinned layers having magnetic moments that are self-pinned antiparallel to each other, the pinned layers being separated by an AP coupling layer constructed of a Ru alloy. The use of a Ru alloy coupling layer significantly increases the pinning field of the AP pinned layer structure over a pure Ru spacer.

MR sensor and thin film media having alloyed Ru antiparallel spacer layer for enhanced antiparallel exchange coupling

A magnetoresistive sensor having a substrate that has been treated with nitrogen (nitrogenated). The nitrogenated substrate includes an alumina base layer and a thin top layer of crystalline alumina that has had a very small amount of nitrogen deposited on top. The amount of nitrogen deposited on top of the alumina is less than or equal to two monolayer, and is preferably less than on monolayer. The amount of nitrogen deposited on top of the alumina substrate is not enough to constitute a layer of nitrogen, but affects the structure of the alumina to cause the alumina to have a desired crystalline structure and an extremely smooth surface.

GMR sensor having an under-layer treated with nitrogen for increased magnetoresistance

A magnetoresistive sensor having a substrate that has been treated with nitrogen (nitrogenated) and having a Ta cap layer with nitrogen added in situ during deposition. The nitrogenated substrate includes an alumina base layer and a thin top layer of crystalline alumina that has had a very small amount of nitrogen deposited on top. The amount of nitrogen deposited on top of the alumina is less than or equal to two monolayer, and is preferably less than on monolayer. The amount of nitrogen deposited on top of the alumina substrate is riot enough to constitute a layer of nitrogen, but affects the structure of the alumina to cause the alumina to have a desired crystalline structure and an extremely smooth surface. The nitrogen in the cap layer can be formed by depositing a Ta cap layer in a sputter deposition chamber having a small amount of nitrogen in an Ar atmosphere.

GMR sensor having layers treated with nitrogen for increased magnetoresistance

A spin valve (SV) sensor of the self-pinned type includes one or more compressive stress modification layers for reducing the likelihood that the pinning field will flip its direction. The spin valve sensor includes a capping layer formed over a spin valve structure which includes a free layer, an antiparallel (AP) self-pinned layer structure, and a spacer layer in between the free layer and the AP self-pinned layer structure. A compressive stress modification layer is formed above or below the capping layer, adjacent the AP self-pinned layer structure, or both. Preferably, the compressive stress modification layer is made of ruthenium (Ru) or other suitable material.

Self-pinned spin valve sensor with stress modification layers for reducing the likelihood of amplitude flip

A magnetic head including a spin valve sensor having a sensor layer stack that includes a pinned magnetic layer, a spacer layer formed on the pinned magnetic layer, and a free magnetic layer formed on the spacer layer. In a preferred embodiment the spacer layer is comprised of CuO. Plasma smoothing of the upper surface of the pinned magnetic layer is conducted prior to depositing the spacer layer, and a preferred plasma gas is a mixture of argon and oxygen.

Spin valve having copper oxide spacer layer with specified coupling field strength between multi-layer free and pinned layer structures

A magnetic head has highly thermally conductive insulator materials containing cobalt-oxide so that heat can more effectively dissipate from the magnetic head. In one illustrative example, the magnetic head has first and second gap layers and a read sensor disposed between the first and the second gap layers. The first and the second gap layers are advantageously made of cobalt-oxide (CoO) (e.g. CoO or CoO), which may exhibit a thermal conductivity of between 5-8 watts/meter-Kelvin or greater. In another illustrative example, a magnetic head is made of a substrate; first and second shield layers; an undercoat layer formed between the substrate and the first shield layer; first and second gap layers formed between the first and the second shield layers; and a read sensor formed between the first and the second gap layers. The undercoat layer is also made of CoO. The improved dissipation of heat from the magnetic head improves the read sensor performance and reduces the likelihood of other problems, such as head-to-disk interface problems.

Magnetic head having highly thermally conductive insulator materials containing cobalt-oxide

A read head is provided having having ultrathin read gap layers with improved insulative properties between a magnetoresistive sensor and ferromagnetic shield layers. The read head comprises a magnetoresistive sensor with first and second shield cap layers made of high resistivity permeable magnetic material formed between the first and second ferromagnetic shields and the first and second insulative read gap layers, respectively. The shield cap layers made of Fe&mdash;Hf&mdash;O material, or alternatively, the Mn&mdash;Zn ferrite material provide highly resistive or insulating soft ferromagnetic layers which add to the electrically insulative read gap layers to provide increased electrical insulation of the spin valve sensor from the metallic ferromagnetic shields while not adding to the magnetic read gap of the read head. The extra insulation provided by the highly resistive shield cap layers makes it possible to use ultrathin insulative first and second read gap layers without increased risk of electrical shorting between the spin valve sensor and the ferromagnetic first and second shields.

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San Jose, CA, United States of America

Wen-yaung Lee