329 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 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.

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.

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.

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°.

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 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.