199results about "Galvano-magnetic devices" patented technology

Disclosed are a high-sensitivity and high-reliability magnetoresistance effect device (MR device) in which bias point designing is easy, and also a magnetic head, a magnetic head assembly and a magnetic recording / reproducing system incorporating the MR device. In the MR device incorporating a spin valve film, the magnetization direction of the free layer is at a certain angle to the magnetization direction of a second ferromagnetic layer therein when the applied magnetic field is zero. In this, the pinned magnetic layer comprises a pair of ferromagnetic films as antiferromagnetically coupled to each other via a coupling film existing therebetween. The device is provided with a means of keeping the magnetization direction of either one of the pair of ferromagnetic films constituting the pinned magnetic layer, and with a nonmagnetic high-conductivity layer as disposed adjacent to a first ferromagnetic layer on the side opposite to the side on which the first ferromagnetic layer is contacted with a nonmagnetic spacer layer. With that constitution, the device has extremely high sensitivity, and the bias point in the device is well controlled.

A hard bias structure for biasing a free layer in a MR element within a magnetic read head is comprised of a soft magnetic underlayer such as NiFe and a hard bias layer comprised of Co78.6Cr5.2Pt16.2 or Co65Cr15Pt20 that are rigidly exchange coupled to ensure a well aligned longitudinal biasing direction with minimal dispersions. The hard bias structure is formed on a BCC seed layer such as CrTi to improve lattice matching. The hard bias structure may be laminated in which each of the underlayers and hard bias layers has a thickness that is adjusted to optimize the total Hc, Mrt, and S values. The present invention encompasses CIP and CPP spin values, MTJ devices, and multi-layer sensors. A larger process window for fabricating the hard bias structure is realized and lower asymmetry output and NBLW (normalized base line wandering) reject rates during a read operation are achieved.

The apparatus for measurement of a current which is flowing in an axially elongated electrical conductor at a first electrical potential. The apparatus contains at least one associated sensor element associated with the conductor that is electrically isolated from it at a second electrical potential different from the first electrical potential of the electrical conductor, and having magnetoresistive characteristics. The sensor element is intended to form a loop which is magnetically closed around the conductor in the circumferential direction, with the resistance value being tapped off at axially opposite ends. Its magnetoresistive part is preferably composed of a non-metallic powder composite material with a high magnetoresistive effect.

A magnetic field sensor has a plurality of vertical Hall elements arranged in at least a portion of a polygonal shape. The magnetic field sensor includes an electronic circuit to process signals generated by the plurality of vertical Hall elements to identify a direction of a magnetic field. A corresponding method of fabricating the magnetic field sensor is also described.

A magnetic head having improved self-pinning. The head includes a sensor having an antiparallel (AP) pinned layer structure, where 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. A pair of compression layers are positioned towards opposite track edges of the sensor. The compression layers provide compressive stress to the sensor.

A method for testing a TMR element includes a step of measuring a plurality of resistances of the TMR element by feeding a plurality of sense currents with different current values each other through the TMR element, a step of calculating a ratio of change in resistance from the measured plurality of resistances of the TMR element, and a step of evaluating the TMR element using the calculated ratio of change in resistance.

A method and an apparatus of a magnetic field sensor structure are disclosed. The magnetic field sensor structure is formed by a bridge of four magnetoresistors (1–4), wherein each magnetoresistor has a longitudinal direction, and each magnetoresistor (1–4) is polarised by magnets (15–19). Also, each magnet has a main magnetisation field along an axial magnetisation direction, and a magnetic leakage field. The polarisation magnets (15–19) and the magnetoresistors (1–4) are arranged in the form of layers on the same substrate. In one embodiment, the polarisation magnets (15–19) are at the same level as the magnetoresistors (1–4) wherein the polarisation magnets (15–19) have the same main magnetisation direction, which is contained in the plane of the layers. The magnetoresistors have their longitudinal direction parallel with that of the axial direction of the magnets. In one embodiment, two magnetoresistors are arranged in the axial field of magnets and two others are in the magnet leakage field.

An extraordinary magnetoresistance (EMR) sensor has a planar shunt and planar leads formed on top of the sensor and extending downward into the semiconductor active region, resulting. Electrically conductive material, such as Au or AuGe, is first deposited into lithographically defined windows on top of the sensor. After liftoff of the photoresist a rapid thermal annealing process causes the conductive material to diffuse downward into the semiconductor material and make electrical contact with the active region. The outline of the sensor is defined by reactive etching or other suitable etching techniques. Insulating backfilling material such as Al-oxide is deposited to protect the EMR sensor and the edges of the active region. Chemical mechanical polishing of the structure results in a planar sensor that does not have exposed active region edges.