Abstract: A magnetic data track used in a magnetic shift register memory system may be fabricated by forming a multilayered stack of alternating dielectric and/or silicon layers. A trench is etched in the multi-layer stack structure. A selective etching process is used to corrugate the walls of trench. A seed layer is applied to the walls and bottom of the trench; the seed layer is covered with a magnetic layer. The trench is filled with an insulating material. A patterned layer is applied and portions of insulating material exposed by the pattern are removed, forming holes. Magnetic material and seed layer exposed in holes is selectively removed. The holes are filled with insulating material and connecting leads are attached to data tracks.

Abstract: A data storage device includes a unpatterned magnetic film having data regions in which to store data. A track is disposed in proximity to the magnetic film, such that the track selectively defines a shiftable magnetic domain wall. In order to select a data bit that is stored in one of the data regions of the magnetic film, a fringing field of the magnetic domain wall in the track is used to selectively change a direction of a magnetic moment in the data region.

Abstract: A magnetic shift register utilizes a data column comprising a thin wire of magnetic material. A writing element selectively changes the direction of the magnetic moment in the magnetic domains to write the data to the data column. Associated with each domain wall are large magnetic fringing fields concentrated in a very small space. These magnetic fringing fields write to and read from the magnetic shift register. When the domain wall is moved close to another magnetic material, the fringing fields change the direction of the magnetic moment in the magnetic material, effectively “writing” to the magnetic material. A reading element similar to a tunneling junction comprises a free layer and a pinned layer of magnetic material. Fringing fields change the direction of the magnetic moment in the free layer with respect to the pinned layer, changing electrical resistance of the reading element and “reading” data stored in the magnetic shift register.

Abstract: A magnetic data track used in a magnetic shift register memory system may be fabricated by forming a multilayered stack of alternating dielectric and/or silicon layers. Vias of approximately 10 microns tall with a cross-section on the order of 100 nm×100 nm are etched in this multilayered stack of alternating layers. Vias may be etched form smooth or notched walls. Vias are filled by electroplating layers of alternating types of ferromagnetic or ferrimagnetic metals. The alternating ferromagnetic or ferrimagnetic layers are comprised of magnetic materials with different magnetization or magnetic exchange or magnetic anisotropies. These different magnetic characteristics allow the pinning of magnetic domain walls at the boundaries between these layers. Alternatively, vias are filled with a homogeneous ferromagnetic material. Magnetic domain walls are formed by the discontinuity in the ferromagnetic or ferromagnetic material that occurs at the notches or at the protuberances along the via walls.

Abstract: A magnetic shift register uses the inherent, natural properties of domain walls in magnetic materials to store data. The shift register uses spin electronics without changing the physical nature of its constituent materials. The shift register comprises a fine track or strip of magnetic materials. Information is stored as domain walls in the track. An electric current is applied to the track to move the magnetic moments along the track past a reading or writing device. In a magnetic material with domain walls, a current passed across the domain wall moves the domain wall in the direction of the current flow. As the current passes through a domain, it becomes “spin polarized”. When this spin polarized current passes through the next domain and across a domain wall, it develops a circle of spin torque. This spin torque moves the domain wall.

Abstract: Digital information is stored in an unpatterned magnetic film, using the inherent, natural properties of the domain walls in ferromagnetic materials to write data on an unpatterned magnetic film. Data is read from the unpatterned magnetic film using magnetic tunneling junctions (MTJs). To achieve sufficient thermal stability, the magnetic fields required to change the orientation of these magnetic regions may be much larger than can be provided by currents passing through wires. This larger magnetic field is achieved by using the domain wall fringing field generated at the boundary between two magnetic domain walls. The magnetic regions are written by using the fringing fields from magnetic domain walls in neighboring magnetic wires. These wires are brought close to the magnetic storage layer where the magnetic storage regions are to be written.

Abstract: A magnetic data track used in a magnetic shift register memory system may be fabricated by forming a multilayered stack of alternating dielectric and/or silicon layers. Vias of approximately 10 microns tall with a cross-section on the order of 100 nm×100 nm are etched in this multilayered stack of alternating layers. Vias may be etched form smooth or notched walls. Vias are filled by electroplating layers of alternating types of ferromagnetic or ferrimagnetic metals. The alternating ferromagnetic or ferrimagnetic layers are comprised of magnetic materials with different magnetization or magnetic exchange or magnetic anisotropies. These different magnetic characteristics allow the pinning of magnetic domain walls at the boundaries between these layers. Alternatively, vias are filled with a homogeneous ferromagnetic material. Magnetic domain walls are formed by the discontinuity in the ferromagnetic or ferromagnetic material that occurs at the notches or at the protuberances along the via walls.

Abstract: A reading device reads the direction of the magnetic moment of domains in a magnetic shift register, thus reading information stored in the domains or bits in the magnetic shift register. Associated with each domain wall are large magnetic fringing fields. The domain wall concentrates the change in magnetism from one direction to another in a very small space. Depending on the nature of the domain wall, very large dipolar fringing fields can emanate from the domain wall. This characteristic of magnetic domains is used to read data stored on to the magnetic shift register. The reading device reads the direction of the magnetic moment in a magnetic shift register, thus reading information stored in the domains.

Abstract: A writing device can change the direction of the magnetic moment in a magnetic shift register, thus writing information to the domains or bits in the magnetic shift register. Associated with each domain wall are large magnetic fringing fields. The domain wall concentrates the change in magnetism from one direction to another in a very small space. Depending on the nature of the domain wall, very large dipolar fringing fields can emanate from the domain wall. This characteristic of magnetic domains is used to write to the magnetic shift register. When the domain wall is moved close to another magnetic material, the large fields of the domain wall change the direction of the magnetic moment in the magnetic material, effectively “writing” to the magnetic material.

Abstract: A magnetic shift register uses the inherent, natural properties of domain walls in magnetic materials to store data. The shift register uses spin electronics without changing the physical nature of its constituent materials. The shift register comprises a fine track or strip of magnetic materials. Information is stored as domain walls in the track. An electric current is applied to the track to move the magnetic moments along the track past a reading or writing device. In a magnetic material with domain walls, a current passed across the domain wall moves the domain wall in the direction of the current flow. As the current passes through a domain, it becomes “spin polarized”. When this spin polarized current passes through the next domain and across a domain wall, it develops a circle of spin torque. This spin torque moves the domain wall.

Abstract: A magnetic shift register uses the inherent, natural properties of domain walls in magnetic materials to store data. The shift register uses spin electronics without changing the physical nature of its constituent materials. The shift register comprises a fine track or strip of magnetic materials. Information is stored as domain walls in the track. An electric current is applied to the track to move the magnetic moments along the track past a reading or writing device. In a magnetic material with domain walls, a current passed across the domain wall moves the domain wall in the direction of the current flow. As the current passes through a domain, it becomes “spin polarized”. When this spin polarized current passes through the next domain and across a domain wall, it develops a circle of spin torque. This spin torque moves the domain wall.

Abstract: A magnetic data track used in a magnetic shift register memory system may be fabricated by forming a multilayered stack of alternating dielectric and/or silicon layers. Vias of approximately 10 microns tall with a cross-section on the order of 100 nm×100 nm are etched in this multilayered stack of alternating layers. Vias may be etched form smooth or notched walls. Vias are filled by electroplating layers of alternating types of ferromagnetic or ferrimagnetic metals. The alternating ferromagnetic or ferrimagnetic layers are comprised of magnetic materials with different magnetization or magnetic exchange or magnetic anisotropies. These different magnetic characteristics allow the pinning of magnetic domain walls at the boundaries between these layers. Alternatively, vias are filled with a homogeneous ferromagnetic material. Magnetic domain walls are formed by the discontinuity in the ferromagnetic or ferromagnetic material that occurs at the notches or at the protuberances along the via walls.

Abstract: A writing device can change the direction of the magnetic moment in a magnetic shift register, thus writing information to the domains or bits in the magnetic shift register. Associated with each domain wall are large magnetic fringing fields. The domain wall concentrates the change in magnetism from one direction to another in a very small space. Depending on the nature of the domain wall, very large dipolar fringing fields can emanate from the domain wall. This characteristic of magnetic domains is used to write to the magnetic shift register. When the domain wall is moved close to another magnetic material, the large fields of the domain wall change the direction of the magnetic moment in the magnetic material, effectively “writing” to the magnetic material.

Abstract: The use of ferrimagnetic materials is proposed for use in magnetic devices. Such magnetic devices include magnetic tunnel junctions (MTJ) which have at least two magnetic layers separated by an insulating barrier layer, wherein at least one of the two magnetic layers is ferrimagnetic. Such MTJ's are used in MRAM (magnetic random access memory) structures. Where the magnetic device is a magnetic sensor, it preferably includes a layer that comprises a ferrimagnetic material separated from another magnetic layer by a barrier layer and the magnetizations of the magnetic layer are oriented at an angle to one another.

Abstract: In order to dampen magnetization changes in magnetic devices, such as magnetic tunnel junctions (MTJ) used in high speed Magnetic Random Access Memory (MRAM), a transition metal selected from the 4d transition metals and 5d transition metals is alloyed into the magnetic layer to be dampened. In a preferred form, a magnetic permalloy layer is alloyed with osmium (Os) in an atomic concentration of between 4% and 15% of the alloy.

Abstract: A magnetic tunnel junction (MTJ) memory cell and a magnetic random access memory (MRAM) incorporating the cells has upper and lower cell electrodes that are formed of bilayers that provide electrical connection between the cells and the copper word and bit lines of the MRAM. The bilayers are formed of a first layer of tantalum nitride or tungsten nitride and a second layer of tantalum or tungsten. In one embodiment TaN is formed directly on the copper and low-resistivity alpha-Ta is formed directly on the TaN. If the cells use an antiferromagnetic layer to fix the moment of the pinned ferromagnetic layer, then Pt—Mn is the preferred material formed over the alpha-Ta. The bilayer can function as a lateral electrode to connect a horizontally spaced-apart cell and a copper stud in the MRAM.

Abstract: A magnetoresistive (MR) sensor comprising a layered structure having at least one trilayer comprising a first and a second thin film ferromagnetic layers separated by and in interfacial contact with a third thin film non-metallic magnetic layer. A fourth thin film layer of material is within the first ferromagnetic layer, and the fourth layer has a thickness between a fraction of a monolayer and several monolayers and is located at predetermined distance from the interface between the first and third layers. A current flow is produced through the MR sensor and variations in resistivity of the MR sensor produced by rotation of the magnetization in one or both of the ferromagnetic layers is sensed as a function of the magnetic field being sensed.

Abstract: A magnetoresistive (MR) sensor based on the giant magnetoresistance (GMR) effect provides a digital output signal. The multilayer stack of alternating ferromagnetic layers and nonferromagnetic metal spacer layers in the GMR sensor has an essentially single crystalline structure so that each of the ferromagnetic layers exhibits uniaxial magnetic anisotropy, i.e. the magnetic moments of the ferromagnetic layers can lie only parallel or antiparallel to a single axis. Unlike GMR multilayers where all of the magnetic moments are affected simultaneously by the external magnetic field, in the present GMR sensor each ferromagnetic layer has its magnetic moment responsive to an external magnetic field strength that is different from the magnetic field strengths at which the magnetic moments of the other ferromagnetic layers are responsive. This allows each ferromagnetic layer to switch its magnetization direction from parallel to antiparallel, or vice versa, independently of the other ferromagnetic layers.

Abstract: A magnetic recording data storage system uses a medium substrate with multiple data layers formed on it and a magnetoresistive (MR) read sensor that provides a direct digital output as it reads data in all the data layers simultaneously. In one disk drive embodiment, the magnetic recording disk is a conventional disk substrate with two magnetically isolated and decoupled magnetic data layers formed on it. Data is written into each of the data layers independently by appropriate selection of the coercivity of the magnetic materials used in the data layers and the strength of the write current in an inductive write head. In one embodiment for independently writing to any of the data layers, the data layers are made of magnetic materials having different coercivity vs. temperature dependencies, and the disk is heated (or not heated) prior to writing with a write field that affects only one of the data layers.

Abstract: A spin valve magnetoresistive (MR) sensor uses a multifilm laminated pinned ferromagnetic layer in place of the conventional single-layer pinned layer. The laminated pinned layer has at least two ferromagnetic films separated by an antiferromagnetically coupling film. By appropriate selection of the thickness of the antiferromagnetically coupling film, depending on the material combination selected for the ferromagnetic and antiferromagnetically coupling films, the ferromagnetic films become antiferromagnetically coupled. In the preferred embodiment, the pinned layer is formed of two films of nickel-iron (Ni--Fe) separated by a ruthenium (Ru) film having a thickness less than approximately 10 .ANG.. Since the pinned ferromagnetic films have their magnetic moments aligned antiparallel with one another, the two moments can be made to essentially cancel one another by making the two ferromagnetic films of substantially the same thickness.