Abstract: Magnetic memories and methods are disclosed. A magnetic memory as described herein includes a plurality of stacked data storage layers to form a three-dimensional magnetic memory. Bits may be written to a data storage layer in the form of magnetic domains. The bits can then be transferred between the stacked data storage layers by heating a neighboring data storage layer, which allows the magnetic fields from the magnetic domains to imprint the magnetic domains in the neighboring data storage layer. By imprinting the magnetic domains into the neighboring data storage layer, the bits are copied from one data storage layer to another.

Abstract: A method and apparatus for oxidizing conductive redeposition in TMR sensors is disclosed. A TMR barrier layer is etched. Redeposition material is oxidized and the barrier is healed using an oxidizing agent selected from the group consisting of ozone and water vapor.

Abstract: Magnetic sensing chips and methods of fabricating the magnetic sensing chips are disclosed. A magnetic sensing chip as described herein includes an EMR sensor formed on a substrate from multiple semiconductor layers. One or more of the semiconductor layers form a quantum well comprising a two-dimensional electron gas (2DEG) or hole gas (2DHG). The magnetic sensing chip also includes one or more transistors formed on the substrate from the multiple semiconductor layers. The transistor(s) likewise include a quantum well comprising a 2DEG or 2DHG. The EMR sensor and the transistor(s) are connected by one or more connections so that the transistor(s) amplifies data signals from the EMR sensor.

Abstract: A structure for preventing Electrostatic Discharge (ESD) damage to a magnetoresistive sensor during manufacture. The structure includes a switching element that can be switched off during testing of the sensor and then switched back on to provide ESD shunting to the sensor. The switch can be a thermally activated mechanical relay built onto the slider. The switch could also be a programmable resistor that includes a solid electrolyte sandwiched between first and second electrodes. One of the electrodes functions as an anode. When voltage is applied in a first direction an ion bridge forms across through the electrolyte across electrodes making the resistor conductive. When a voltage is applied in a second direction, the ion bridge recedes and the programmable resistor becomes essentially non-conductive.

Abstract: A magnetic head including a second magnetic pole (P2 pole) that is fabricated upon a write gap layer that is deposited upon a flat surface. To achieve the flat surface, a P1 pole pedestal is formed upon the P1 pole layer with a sufficient thickness that the induction coil structure can be fabricated beneath the write gap layer. In the preferred embodiment, an etch stop layer is formed upon the P1 pole layer and an ion etching process is utilized to form the induction coil trenches in an etchable material that is deposited upon the etch stop layer. Following the fabrication of the induction coil structure a CMP process is conducted to obtain a polished flat surface upon which to deposit the write gap layer, and the P2 pole is then fabricated upon the flat write gap layer.

Abstract: The magnetic head of the present invention, includes a second magnetic pole (P2 pole) that is fabricated upon a write gap layer that is deposited upon a flat surface. To achieve the flat surface, a P1 pole pedestal is formed upon the P1 pole layer with a sufficient thickness that the induction coil structure can be fabricated beneath the write gap layer. In the preferred embodiment, an etch stop layer is formed upon the P1 pole layer and an ion etching process is utilized to form the induction coil trenches in an etchable material that is deposited upon the etch stop layer. Following the fabrication of the induction coil structure a CMP process is conducted to obtain a polished flat surface upon which to deposit the write gap layer, and the P2 pole is then fabricated upon the flat write gap layer. The magnetic head of the present invention can be reliably fabricated with a more narrow P2 pole tip base width, such that data tracks written by the magnetic head are likewise narrower.

Abstract: A current-perpendicular-to the-plane (CPP) magnetoresistive device has two ferromagnetic layers separated by a nonmagnetic spacer layer with the free ferromagnetic layer having a central region of ferromagnetic material and nonmagnetic side regions formed of one or more oxides of the ferromagnetic material. One type of CPP device is a magnetic tunnel junction (MTJ) magnetoresistive read head in which the lower pinned layer has a width and height greater than the width and height, respectively, of the overlying central region of the upper free layer, with the side regions of the free layer being oxidized and therefore nonmagnetic. The MTJ read head is formed by patterning resist in the shape of the free layer central region over the stack of layers in the MTJ, ion milling or etching the stack down into the free layer, and then exposing the stack to oxygen to oxidize the ferromagnetic material in the side regions not covered by the resist.

Abstract: A method and structure for a spin valve transistor (SVT) comprises a magnetic field sensor, an insulating layer adjacent the magnetic field sensor, a bias layer adjacent the insulating layer, a non-magnetic layer adjacent the bias layer, and a ferromagnetic layer over the non-magnetic layer, wherein the insulating layer and the non-magnetic layer comprise antiferromagnetic materials. The magnetic field sensor comprises a base region, a collector region adjacent the base region, an emitter region adjacent the base region, and a barrier region located between the base region and the emitter region. The bias layer is between the insulating layer and the non-magnetic layer. The bias layer is magnetic and is at least three times the thickness of the magnetic materials in the base region.

Abstract: A method and structure for a spin valve transistor (SVT) comprises a magnetic field sensor, a first insulating layer adjacent the magnetic field sensor, a bias layer adjacent the insulating layer, a second insulating layer adjacent the bias layer, and a ferromagnetic layer over the second insulating layer, wherein the first insulating layer and the second insulating layer comprise antiferromagnetic materials. The magnetic field sensor comprises a base region, a collector region adjacent the base region, an emitter region adjacent the base region, and a barrier region located between the base region and the emitter region. The bias layer is between the first insulating layer and the second insulating layer. The bias layer is magnetic and is at least three times the thickness of the base region.

Abstract: A magnetic tunnel junction (MTJ) device usable as a magnetic memory cell or magnetoresistive sensor, such as a MTJ read head for magnetic recording, has the free ferromagnetic layer located on the bottom of the device, the bottom free layer being formed on a special underlayer. The MTJ read head may be a flux-guided head that uses the free layer as a flux guide for directing magnetic flux from the magnetic media to the sensing region of the MTJ. The special underlayer for the growth of the free layer is an alloy comprising Mn, one of Pt, Ni, Ir and Os, and an additive X selected from Ta, Al, Ti, Cu, Cr and V. Without the additive, the underlayer alloy is antiferromagnetic. The additive is present in an amount sufficient to render the alloy to have no magnetic ordering, i.e., it is neither antiferromagnetic nor ferromagnetic, but without substantially affecting the preferred crystalline texture and unit cell size so that the underlayer is well-suited as a growth-enhancing underlayer for the free layer.

Abstract: A current-in-the-plane (CIP) giant magnetoresistive (GMR) spin valve sensor has its free layer magnetization stabilized by longitudinal biasing through the use of free layer end-region antiferromagnetic exchange coupling. An antiparallel coupling (APC) layer, such as Ru, is formed on the free layer and a ferromagnetic bias layer is formed on the APC layer. The bias layer is a continuous layer that extends across the entire width of the free layer. The central region of the bias layer is formed of nonmagnetic oxides of one or more of the elements making up the bias layer, with the bias layer end regions remaining ferromagnetic. The oxidized central region of the bias layer defines the central active trackwidth region of the underlying free layer. The ferromagnetic end regions of the bias layer are antiferromagnetically coupled across the APC layer to the corresponding underlying free layer end regions to provide the longitudinal biasing.

Abstract: The magnetic head of the present invention, includes a second magnetic pole (P2 pole) that is fabricated upon a write gap layer that is deposited upon a flat surface. To achieve the flat surface, a P1 pole pedestal is formed upon the P1 pole layer with a sufficient thickness that the induction coil structure can be fabricated beneath the write gap layer. In the preferred embodiment, an etch stop layer is formed upon the P1 pole layer and an ion etching process is utilized to form the induction coil trenches in an etchable material that is deposited upon the etch stop layer. Following the fabrication of the induction coil structure a CMP process is conducted to obtain a polished flat surface upon which to deposit the write gap layer, and the P2 pole is then fabricated upon the flat write gap layer.

Abstract: A current-perpendicular-to the-plane (CPP) magnetoresistive device has two ferromagnetic layers separated by a nonmagnetic spacer layer with the free ferromagnetic layer having a central region of ferromagnetic material and nonmagnetic side regions formed of one or more oxides of the ferromagnetic material. One type of CPP device is a magnetic tunnel junction (MTJ) magnetoresistive read head in which the lower pinned layer has a width and height greater than the width and height, respectively, of the overlying central region of the upper free layer, with the side regions of the free layer being oxidized and therefore nonmagnetic. The MTJ read head is formed by patterning resist in the shape of the free layer central region over the stack of layers in the MTJ, ion milling or etching the stack down into the free layer, and then exposing the stack to oxygen to oxidize the ferromagnetic material in the side regions not covered by the resist.

Abstract: A magnetization of a ferromagnetic free layer of a current-in-plane (CIP) sensor is stabilized using an in-stack longitudinal bias structure that includes a ferromagnetic bias layer and an anti-ferromagnetic bias layer. An electrically insulating layer separates the ferromagnetic free layer and the in-stack longitudinal bias structure, and thus the leads attached to the CIP sensor do not make direct electrical contact with the in-stack longitudinal bias structure. As a result, the sense current shunted by the in-stack longitudinal bias structure is prevented. Since a width along the off track direction of the in-stack longitudinal bias structure is greater than the track-width of the CIP sensor, the edge magnetostatic coupling filed acting on the ferromagnetic free layer from the track width edges of the in-stack longitudinal bias structure is reduced to approximately zero.

Abstract: A flux guided magnetic tunnel junction head includes a ferromagnetic pinned layer having an active region with a front edge recessed from a sensing surface, and a non-active region located between the sensing surface and the active region. The non-active region of the ferromagnetic pinned layer is rendered substantially non-conducting by chemically processing the ferromagnetic material of the ferromagnetic pinned layer in this region. The flux guided MTJ head also includes a ferromagnetic free layer having a front edge substantially coplanar with a sensing surface. The ferromagnetic free layer can function as a flux guide to direct magnetic flux from a recording medium to the tunnel junction. The location of the front edge of the ferromagnetic pinned layer prevents any shorting of the flux guided MTJ head occurring when the head is lapped at the sensing surface.

Abstract: A flux guided magnetic tunnel junction head includes a ferromagnetic pinned layer having an active region with a front edge recessed from a sensing surface, and a non-active region located between the sensing surface and the active region. The non-active region of the ferromagnetic pinned layer is rendered substantially non-conducting by chemically processing the ferromagnetic material of the ferromagnetic pinned layer in this region. The flux guided MTJ head also includes a ferromagnetic free layer having a front edge substantially coplanar with a sensing surface. The ferromagnetic free layer can function as a flux guide to direct magnetic flux from a recording medium to the tunnel junction. The location of the front edge of the ferromagnetic pinned layer prevents any shorting of the flux guided MTJ head occurring when the head is lapped at the sensing surface.

Abstract: A current-perpendicular-to-the-plane (CPP) magnetoresistive sensor or read head has a magnetic shield geometry that covers the side walls of the sensor structure to prevent side reading caused by magnetic flux entering from adjacent data tracks. The shield geometry includes a bottom shield with a substantially planar surface and a specially shaped top shield. The top shield has substantially vertical portions generally parallel to the side walls of the sensor structure, a horizontal top portion over the trackwidth region of the sensor, and horizontal side portions formed over the portions of the bottom shield on either side of the sensor structure. The insulating gap material that separates the bottom and top shields is in contact with the horizontal portions of the bottom shield and the side walls of the sensor structure.

Abstract: A write head has a second pole tip layer, a coil layer and a write coil insulation layer that are planarized at their top surfaces. A thin top insulation layer insulates the top of the coil layer from a yoke portion of the second pole piece which is connected to the second pole tip layer in the pole tip region and connected to a first pole piece layer in a back gap region. In a preferred embodiment the write gap layer extends throughout the yoke region and provides the only insulation between the first pole piece layer and the coil layer. Further, it is preferred that the write coil insulation layer be an inorganic material such as silicon dioxide (SiO2). Several embodiments of the write head are provided along with novel methods of making.

Abstract: The back end of an MR sensor and a flux guide are joined by a contiguous self-aligned junction so that a predictable overlap of the flux guide on the back end of the MR sensor can be achieved for optimizing signal flux density in the MR sensor. Lead/longitudinal bias layers for the MR sensor are also joined by a contiguous selfaligned junction to the flux guide for stabilizing the flux guide. By employing a single lift off resist mask the MR sensor and the lead/longitudinal bias layers can be patterned followed by deposition of the flux guide. The flux guide is a bilayer of an insulation material layer and a flux guide material layer. The insulation material layer is sandwiched between the MR sensor and the flux guide material layer and between the lead/longitudinal bias layers and the flux guide material layer. A heat guide or combined flux guide and heat guide may be substituted for the aforementioned flux guide.

Abstract: A write head has a second pole tip layer, a coil layer and a write coil insulation layer that are planarized at their top surfaces. A thin top insulation layer insulates the top of the coil layer from a yoke portion of the second pole piece which is connected to the second pole tip layer in the pole tip region and connected to a first pole piece layer in a back gap region. In a preferred embodiment the write gap layer extends throughout the yoke region and provides the only insulation between the first pole piece layer and the coil layer. Further, it is preferred that the write coil insulation layer be an inorganic material such as silicon dioxide (SiO2). Several embodiments of the write head are provided along with novel methods of making.