333 results about "Tunnel magnetoresistance" patented technology

The present invention provides a tunneling magneto-resistive read sensor structure that improves sensitivity and linear density of the sensor structure. The sensor includes first and second electrodes and a stack positioned between the electrodes. The stack includes first and second free layers with magnetization orientations that are biased relative to each other. A tunneling barrier (insulating layer) or non-magnetic metal spacer is positioned between the first and second free layers. A sense current is passed between the first and second free layers of the stack. The amount of current passing through the first and second free layer changes based upon the orientation of the first and second free layers relative to each other.

A method of producing a magnetoresistive read head and a tunneling magnetoresistive read head produced thereby are disclosed. A shield layer is provided. A magnetic etch-stop layer is formed over the shield layer, where the magnetic etch-stop layer comprises a nonmagnetic metal and a soft magnetic material with overall property still being magnetically soft. A sensor stack is formed over the magnetic etch-stop layer. A patterned mask layer is formed over the sensor stack. Material from a portion of the sensor stack not covered by the patterned mask is removed.

A tunneling magnetoresistance (TMR) read head and a method of producing the same are disclosed. A free layer having a free layer stripe height is provided, the free layer having a first side and a second side. A tunneling barrier layer is formed adjacent to the first side of the free layer, the tunneling barrier layer having a first side and a second side, the second side of the tunneling barrier layer facing the first side of the free layer. A pinned stack is formed adjacent to the first side of the tunneling barrier layer. The pinned stack comprises at least one magnetic layer having a current path stripe height that is less than the free layer stripe height.

A method of fabricating a tunneling magnetoresistance (TMR) reader is disclosed. A TMR structure comprising at least one ferromagnetic layer and at least one nonmagnetic insulating layer is provided. A first thermal annealing process on the TMR structure is performed. A reader pattern definition process performed on the TMR structure to obtain a patterned TMR reader. A second thermal annealing process is performed on the patterned TMR reader.

A read sensor for a read transducer is fabricated. The read transducer has field and device regions. A read sensor stack is deposited. A mask covering part of the stack corresponding to the read sensor is provided. The read sensor having inboard and outboard junction angles is defined from the stack in a track width direction. A critical junction (CJ) focused ion beam scan (FIBS) polishing that removes part of the read sensor based on the junction angles is performed. A hard bias structure is deposited and the transducer planarized. A remaining portion of the mask is removed. A stripe height mask covering part of the read sensor and hard bias structure in a stripe height direction is provided. The read sensor stripe height is defined. A tunneling magnetoresistance (TMR) FIBS polishing that removes part of the stack in the field region is performed. An insulating layer is provided.

Magnetic tunnel junctions are constructed from a MgO or Mg—ZnO tunnel barrier and amorphous magnetic layers in proximity with, and on respective sides of, the tunnel barrier. The amorphous magnetic layer preferably includes Co and at least one additional element selected to make the layer amorphous, such as boron. Magnetic tunnel junctions formed from the amorphous magnetic layers and the tunnel barrier have tunneling magnetoresistance values of up to 200% or more.

ZnMg oxide tunnel barriers are grown which, when sandwiched between ferri- or ferromagnetic layers, form magnetic tunnel junctions exhibiting high tunneling magnetoresistance (TMR). The TMR may be increased by annealing the magnetic tunnel junctions. The zinc-magnesium oxide tunnel barriers may be incorporated into a variety of other devices, such as magnetic tunneling transistors and spin injector devices. The ZnMg oxide tunnel barriers are grown by first depositing a zinc and / or magnesium layer onto an underlying substrate in oxygen-poor (or oxygen-free) conditions, and subsequently depositing zinc and / or magnesium onto this layer in the presence of reactive oxygen.

The magnetic tape device including: a magnetic tape; and a servo head, in which the servo head is a magnetic head including a tunnel magnetoresistance effect type element as a servo pattern reading element, the magnetic tape includes a non-magnetic support, and a magnetic layer including ferromagnetic powder and a binding agent on the non-magnetic support, the magnetic layer includes a servo pattern, and logarithmic decrement acquired by a pendulum viscoelasticity test performed regarding a surface of the magnetic layer is equal to or smaller than 0.050.

The magnetic tape device includes: a magnetic tape; and a reproducing head, in which a magnetic tape transportation speed of the magnetic tape device is equal to or lower than 18 m / sec, the reproducing head is a magnetic head including a tunnel magnetoresistance effect type element as a reproducing element, the magnetic tape includes a non-magnetic support, and a magnetic layer including ferromagnetic hexagonal ferrite powder, non-magnetic powder, and a binding agent on the non-magnetic support, and a tilt cos θ of the ferromagnetic hexagonal ferrite powder with respect to a surface of the magnetic layer acquired by cross section observation performed by using a scanning transmission electron microscope is 0.85 to 0.95.

The magnetic tape device includes: a magnetic tape; and a servo head, in which a magnetic tape transportation speed of the magnetic tape device is equal to or lower than 18 m / sec, the servo head is a magnetic head including a tunnel magnetoresistance effect type element as a servo pattern reading element, the magnetic tape includes a non-magnetic support, and a magnetic layer including ferromagnetic powder and a binding agent on the non-magnetic support, the magnetic layer includes a servo pattern, and a coefficient of friction measured regarding a base portion of a surface of the magnetic layer is equal to or smaller than 0.30.

The magnetic tape device includes: a magnetic tape; and a reproducing head, in which the reproducing head is a magnetic head including a tunnel magnetoresistance effect type element as a reproducing element, the magnetic tape includes a non-magnetic support, and a magnetic layer including ferromagnetic powder and a binding agent on the non-magnetic support, and logarithmic decrement acquired by a pendulum viscoelasticity test performed regarding the surface of the magnetic layer is equal to or smaller than 0.050.

The magnetic tape device includes: a magnetic tape; and a reproducing head, in which a magnetic tape transportation speed of the magnetic tape device is equal to or lower than 18 m / sec, the reproducing head is a magnetic head including a tunnel magnetoresistance effect type element as a reproducing element, the magnetic tape includes a non-magnetic support, and a magnetic layer including ferromagnetic powder and a binding agent on the non-magnetic support, the magnetic layer includes one or more components selected from the group consisting of fatty acid and fatty acid amide, and a C—H derived C concentration calculated from a C—H peak area ratio of C1s spectra obtained by X-ray photoelectron spectroscopic analysis performed on the surface of the magnetic layer at a photoelectron take-off angle of 10 degrees is 45 to 65 atom %.

A magnetic tunneling element is constructed from a MgO or Mg—ZnO tunnel barrier and an amorphous magnetic layer in proximity with the tunnel barrier. The amorphous magnetic layer includes Co and at least one additional element selected to make the layer amorphous. Magnetic tunnel junctions formed from the amorphous magnetic layer, the tunnel barrier, and an additional ferromagnetic layer have tunneling magnetoresistance values of up to 200% or more.

A magnetic tunnel junction stack is provided that includes nonmagnetic spacer layers between the free layer and the polarizer layer formed from magnesium oxide and tantalum nitride materials that balance the spin torques acting on the free layer. The design provided enables a deterministic final state for the storage layer and significantly improves the tunneling magnetoresistance value and switching characteristics of the magnetic tunnel junction for MRAM applications.

The a magnetic tape device includes: a magnetic tape; and a reproducing head, in which a magnetic tape transportation speed of the magnetic tape device is equal to or lower than 18 m / sec, the reproducing head is a magnetic head including a tunnel magnetoresistance effect type element as a reproducing element, the magnetic tape includes a non-magnetic support, and a magnetic layer including ferromagnetic powder and a binding agent on the non-magnetic support, and a contact angle with respect to 1-bromonaphthalene measured regarding a surface of the magnetic layer is 48.0° to 53.0°.

A magnetic tunneling element is constructed from a MgO or Mg—ZnO tunnel barrier and an amorphous magnetic layer in proximity with the tunnel baffler. The amorphous magnetic layer includes Co and at least one additional element selected to make the layer amorphous. Magnetic tunnel junctions formed from the amorphous magnetic layer, the tunnel barrier, and an additional ferromagnetic layer have tunneling magnetoresistance values of up to 200% or more.

A high performance TMR sensor is fabricated by employing a composite inner pinned (AP1) layer in an AP2 / Ru / AP1 pinned layer configuration. In one embodiment, there is a 10 to 80 Angstrom thick lower CoFeB or CoFeB alloy layer on the Ru coupling layer, a and 5 to 50 Angstrom thick Fe or Fe alloy layer on the CoFeB or CoFeB alloy, and a 5 to 30 Angstrom thick Co or Co rich alloy layer formed on the Fe or Fe alloy. A MR ratio of about 48% with a RA of <2 ohm-um2 is achieved when a CoFe AP2 layer, MgO (NOX) tunnel barrier, and CoFe / NiFe free layer are used in the TMR stack. Improved RA uniformity and less head noise are observed. Optionally, a CoFe layer may be inserted between the coupling layer and CoFeB or CoFeB alloy layer to improve pinning strength and enhance crystallization.

A tunneling magneto-resistive reader includes a sensor stack separating a top magnetic shield from a bottom magnetic shield. The sensor stack includes a reference magnetic element having a reference magnetization orientation direction and a free magnetic element having a free magnetization orientation direction substantially perpendicular to the reference magnetization orientation direction. A non-magnetic spacer layer separates the reference magnetic element from the free magnetic element. A first side magnetic shield and a second side magnetic shield is disposed between the top magnetic shield from a bottom magnetic shield, and the sensor stack is between the first side magnetic shield and the second side magnetic shield. The first side magnetic shield and the second side magnetic shield electrically insulates the top magnetic shield from a bottom magnetic shield.

Provided is a high-speed and ultra-low-power-consumption nonvolatile memory having a high temperature stability at a zero magnetic field. In a tunnel magnetoresistive film constituting a nonvolatile magnetic memory that employs a writing method using a spin-transfer torque, an insulating layer and a nonmagnetic conductive layer are stacked above a ferromagnetic free layer.

A fabrication process for a tunneling magnetoresistance (TMR) sensor is disclosed. In particular, a unique method of forming a barrier layer of the TMR sensor is utilized so that the TMR sensor exhibits good magnetic and TMR properties. In one particular example, the barrier layer is formed by depositing a metallic film in an argon gas in a DC magnetron sputtering module, depositing an oxygen-doped metallic film in mixed xenon and oxygen gases in an ion-beam sputtering module, and oxidizing these films in an oxygen gas in an oxygen treatment module. This three-step barrier layer formation process minimizes oxygen penetration into ferromagnetic (FM) sense and pinned layers of the TMR sensor and optimally controls oxygen doping into the barrier layer. As a result, the FM sense and pinned layers exhibit controlled magnetic properties, the barrier layer provides a low junction resistance-area product, and the TMR sensor exhibits a high TMR coefficient.

An MTJ (magnetic tunneling junction) device particularly suitable for use as an MRAM (magnetic random access memory) or a tunneling magnetoresistive (TMR) read sensor, is formed on a seed layer which allows the tunneling barrier layer to be ultra-thin, smooth, and to have a high breakdown voltage. The seed layer is a layer of NiCr which is formed on a sputter-etched layer of Ta. The tunneling barrier layer for the MRAM is formed from a thin layer of Al which is radically oxidized (ROX), in-situ, to form the layer with characteristics described above. The tunneling barrier layer for the read sensor formed from a thin layer of Al or a HfAl bilayer which is naturally oxidized (NOX), in situ, to form the barrier layer. The resulting device has generally improved performance characteristics in terms of GMR ratio and junction resistance.

A spin-torque oscillator (STO) has a single free ferromagnetic layer that forms part of both a giant magnetoresistance (GMR) structure with a nonmagnetic conductive spacer layer and a tunneling magnetoresistance (TMR) structure with a tunnel barrier layer. The STO has three electrical terminals that connect to electrical circuitry that provides a spin-torque excitation current through the conductive spacer layer and a lesser sense current through the tunnel barrier layer. When the STO is used as a magnetic field sensor, the excitation current causes the magnetization of the free layer to oscillate at a fixed base frequency in the absence of an external magnetic field. A detector coupled to the sense current detects shifts in the free layer magnetization oscillation frequency from the base frequency in response to external magnetic fields.

Magnetic tunneling devices are formed from a first body centered cubic (bcc) magnetic layer and a second bcc magnetic layer. At least one spacer layer of bcc material between these magnetic layers exchange couples the first and second bcc magnetic layers. A tunnel barrier in proximity with the second magnetic layer permits spin-polarized current to pass between the tunnel barrier and the second layer; the tunnel barrier may be either MgO and Mg—ZnO. The first magnetic layer, the spacer layer, the second magnetic layer, and the tunnel barrier are all preferably (100) oriented. The MgO and Mg—ZnO tunnel barriers are prepared by first depositing a metallic layer on the second magnetic layer (e.g., a Mg layer), thereby substantially reducing the oxygen content in this magnetic layer, which improves the performance of the tunnel barriers.

In a tunnel magnetoresistance effect element comprising a tunnel multilayered film having a tunnel barrier layer, a ferromagnetic free layer and a ferromagnetic pinned layer such that the tunnel barrier layer is held between the ferromagnetic free layer and the ferromagnetic pinned layer, three indexes representing a surface roughness state of the tunnel barrier layer are set such that Ra<=1 nm, Rmax<=10 nm and Rrms<=1.2 nm, wherein Ra is one of the three indexes and representing the center line average roughness, Rmax is one of the three indexes and representing the maximum height, and Rrms is one of the three indexes and representing the standard deviation roughness. Thus, the tunnel magnetoresistance effect element exhibits improved characteristics, particularly, a large head output.

Spin-torque devices are based on a combination of giant magnetoresistance (GMR) and tunneling magnetoresistance (TMR) effects. The basic structure has various applications, including amplifiers, oscillators, and diodes. For example, if the low-magnetoresistance contact is biased below a critical value, the device may function as a microwave-frequency selective amplifier. If the low-magnetoresistance contact is biased above the critical value, the device may function as a microwave oscillator. A plurality of low- and high-magnetoresistance contact pairs may be induced to oscillate in a phase-locked regime, thereby multiplying output power. The frequency of operation of these devices will be tunable by the external magnetic field, as well as by the direct bias current, in the frequency range between 10 and 100 GHz. The devices do not use semiconductor materials and are expected to be exceptionally radiation-hard, thereby finding application in military nanoelectronics.

A double-barrier structure based magnetic memory device is disclosed. The double-barrier structure is used to strengthen perpendicular magnetic anisotropy or tunnel magnetoresistance ratio of a magnetic tunnel junction; meanwhile, a three-port device based on a spin orbit torque is formed by combination of metal wire at the bottom; the double-barrier structure of the magnetic memory device comprises a metal oxide barrier layer, a free layer formed by ferromagnetic metal and the other metal oxide barrier layer; a reference layer formed by the ferromagnetic metal and a covering layer formed by non-magnetic metal are deposited on the top of the structure in sequence; the top of the structure is connected with a peripheral circuit through a metal electrode; and the wire at the bottom is formed by metal materials with a larger hall angle and used for data writing. By introducing the double-barrier structure into the magnetic memory device based on the spin orbit torque, the adverse effect on the data writing caused by too high resistance can be effectively avoided, and the thermal stability and the tunnel magnetoresistance ratio of the device are improved; and the good property of the STT-MRAM is maintained by the device, and the double-barrier structure based magnetic memory device is quite suitable for industrial production.

By varying only the thickness of a known material having superior magnetic characteristics to increase spin polarization without changing the chemical composition, a tunnel magnetoresistive element capable of producing a larger magnetoresistive effect is provided. The tunnel magnetoresistive element includes an underlayer (nonmagnetic or antiferromagnetic metal film); an ultrathin ferromagnetic layer disposed on the underlayer; an insulating layer disposed on the ultrathin ferromagnetic layer; and a ferromagnetic electrode disposed on the insulating layer.