228results about "Magnetostrictive property measurements" patented technology

A method and system for providing a magnetic element are described. The method and system include providing a pinned layer, fabricating a metallic spacer layer and oxidizing a portion of the spacer layer in an environment including at least oxygen and a gas inert with respect to the spacer layer to provide an oxide layer. The method and system also include creating a free layer. The oxide layer is between a remaining metallic portion of the spacer layer and the free layer. In one aspect, the system includes a chamber and a gas diffusion apparatus within the chamber. The gas diffusion apparatus includes a plurality of nozzles and defines a plane. The gas exits each of the plurality of nozzles in a cone having an apex angle. The nozzles are directed at a nozzle tilt angle of at least half of the apex angle from the plane and the spacer layer.

A high performance TMR sensor is fabricated by employing a free layer comprised of CoB_X with a λ between −5×10⁻⁶ and 0 on a MgO_X tunnel barrier. Optionally, a FeCo/CoB_X free layer configuration may be used where x is about 1 to 30 atomic %. Trilayer configurations represented by FeCo/CoFeB/CoB_X, FeCo/CoB_X/CoFeB, FeCo_Y/CoFe_W/CoB_X, or FeCo_Y/FeB/CoB_X may also be employed. Alternatively, CoNiFeB or CoNiFeBM formed by co-sputtering CoB with CoNiFe or CoNiFeM, respectively, where M is V, Ti, Zr, Nb, Hf, Ta, or Mo may be substituted for CoBx in the aforementioned embodiments. A 15 to 30% in improvement in TMR ratio over a conventional CoFe/NiFe free layer is achieved while maintaining a low Hc and RA<3 ohm-um². In bilayer or trilayer embodiments, λ between −5×10⁻⁶ and 5×10⁻⁶ is achieved by combining CoBx (−λ) and one or more layers having a positive λ.

A magnetic field sensor circuit comprises a first magneto-resistive sensor (Rx) which senses a first magnetic field component in a first direction to supply a first sense signal (Vx). A first flipping coil (FC1) applies a first flipping magnetic field with a periodically changing polarity to the first magneto-resistive sensor (Rx) to cause the first sense signal (Vx) to have alternating different levels synchronized with the first flipping magnetic field. A second magneto -resistive sensor (Ry) senses a second magnetic field component in a second direction different than the first direction to supply a second sense signal (Vy). A second flipping coil (FC2) applies a second flipping magnetic field with a periodically changing polarity to the second magneto -resistive sensor (Ry) to cause the second sense signal (Vy) to have an alternating different levels synchronized with the second flipping magnetic field. The first flipping magnetic field and the second flipping magnetic field have a phase shift. A differential amplifier (AMP1) receives the first sense signal (Vx) and the second sense signal (Vy) to obtain a difference signal (Vd). A first synchronous demodulator (DEM1) receives the difference signal (Vd) and a first switching signal (Q1) being phase locked to the alternating different levels of the first sense signal (Vx) to supply a first output signal (Vox) indicating the first magnetic field component. A second synchronous demodulator (DEM2) receives the difference signal (Vd) and a second switching signal (Q2) being phase locked to the alternating different levels of the second sense signal (Vy) to supply a second output signal (Voy) indicating the second magnetic field component.

Small implantable magnetostrictive-electroactive (ME) device for delivering electrical energy to surrounding tissue. The wireless ME device is activated by a changing magnetic field from an externally applied alternating magnetic field source. The ME device provides a means for stimulating a nerve, tissue or internal organ with direct electrical current, such as relatively low-level direct current for temporary or as needed therapy. The field source (e.g. small coil antenna) may be a hand-held device or affixed to the wearer's skin, clothing or accessories. The ME implant may be configured as pellets which are small enough to be implanted through a surgical needle. In one embodiment, the wireless energy transmission system can be used for stimulating bone growth.

Apparatus and method for harvesting energy from the environment and/or other external sources and converting it to useful electrical energy. The harvester does not contain a permanent magnet or other local field source but instead relies on the earth's magnetic field of another source of a magnetic field that is external to the sensing device. One advantage of these new harvesters is that they can be made smaller and lighter than energy harvesters that contain a magnet and/or an inertial mass.

An ultrasensitive room temperature magnetoelectric thin film magnetometer is fabricated on a cantilever beam and includes an active magnetoelectric multilayer structure having a plurality of thin films formed at a region defined on the cantilever beam. Upon application of a magnetic field, the active magnetoelectric structure generates a corresponding response of an electrical nature which is a measure of a value of the applied magnetic field. The material of the cantilever beam may be removed beneath the active magnetoelectric multilayer structure to form a freestanding modification of the magnetometer with superior sensitivity. The active magnetoelectric multilayer structure is either a bi-layer structure which includes a piezoactive (piezoelectric and/or piezoresistive) thin film deposited in contact with a magnetostrictive thin film or a tri-layer active structure (in the free-standing implementation) including a piezoactive thin film sandwiched between a pair of magnetostrictive thin films.

A magnetic field sensor including a body including a magnetic mechanism capable of forming a torque applied on the body by action of an external magnetic field to be detected; a connector, separated from the body, mechanically connecting the body to an inlay portion of the sensor by at least one pivot link having an axis perpendicular to the direction of the magnetic field to be detected; a detector detecting stress applied by the body by action of the torque, separated from the connector and including at least one suspended stress gauge including a first part mechanically connected to the inlay portion, a second part mechanically connected to the body, and a third part provided between the first and second parts and suspended between the inlay portion and the body.

A magnetic memory device includes a magnetic tunnel junction having a free magnetic layer having a magnetization orientation that is switchable between a high resistance state magnetization orientation and a low resistance state magnetization orientation and a memristor solid state element electrically coupled to the magnetic tunnel junction. The memristor has a device response that is an integrated voltage versus an integrated current.

A magnetic field sensor comprises one or more magnetic layers of magnetostrictive material that is mechanically bonded to one or more layers of electroactive material. When a magnetic field is applied to the device, it rotates the magnetization that is present in the in the magnetostrictive material thereby generating a magnetostrictive stress in the material. The magnetostrictive stress generated by this layer, in turn, stresses the piezoelectric layer to which the magnetostrictive layer is bonded. In order to increase sensitivity, the voltage across the piezoelectric material is measured in a direction that is parallel to the plane in which the magnetization in the magnetic material rotates.

A segmented magnetostrictive patch array transducer capable of generating a high frequency shear wave in a structure such as a rod or a pipe, a structural fault diagnosing apparatus including the segmented magnetostrictive patch array transducer, and a method of operating the segmented magnetostrictive patch array transducer are shown. The segmented magnetostrictive patch array transducer includes a plurality of magnetostrictive patches attached along a circumference of a rod member; a plurality of insulators that are disposed on the magnetostrictive patches; a plurality of meander coils, each of the meander coils comprising a plurality of coil lines extending along the circumference direction of the rod member on each of the insulators, wherein a current flows through adjacent coil lines in opposite directions to one another; and a plurality of magnets that respectively form a magnetic field along the circumferential direction of the rod member on the magnetostrictive patches.

An apparatus (10) is set forth for measuring a return signal of a magnetostrictive sensor (20) that detects a force, torque, or pressure. The return signal includes noise, a DC resistance (44), an AC resistance and an inductance and the inductance is shifted ninety degrees from the AC resistance. The apparatus (10) includes a sensor filter (22) to remove the noise from the return signal. A sensor filter (22) shifts the return signal and more specifically, the inductance by an additional angle and the sum of the additional angle and the ninety degrees phase shift is defined as the final detection angle. To detect the inductance at the final detection angle, a wave filter (16) and a reference filter (28) shifts a reference signal by the final detection angle to trigger a first demodulator (26) to detect the inductance at the final detection angle. The inductance detected by the first demodulator (26) varies due to temperature. To remove the temperature from the measured inductance, the apparatus includes a DC detection circuit (42) to detect the DC resistance which is proportional to the temperature across the sensor (20). The DC resistance and the measure inductance are inserted into a correction equation to produce a corrected inductance which is independent of temperature. Instead of inductance, an AC resistance may be used in the equation.

Methods and devices for inspecting waterwall tubes for the detection of fire side damage over a long length of the tube are described. The system of the invention uses a magnetostrictive strip and a flat coil-type plate magnetostrictive sensor (MsS) that are held in place on the waterwall using a specially designed frame and an electromagnetic circuit. The magnetostrictive strip and plate type MsS are positioned against a tube in the waterwall using an elastomeric pad or a fluid filled bladder to achieve close contact and good mechanical coupling between the magnetostrictive strip and the tube surface. When current activated, the electromagnet holds the entire assembly in place and provides a DC bias magnetic field required for plate magnetostrictive sensor probe operation. Long-range guided-waves are pulsed into the tube and reflected signals are detected within the same sensor structure. The received signal data representative of a long section of the tube under investigation is then analyzed for the presence of anomalies and defects. When data acquisition for a particular tube or tube section is completed the electromagnet is turned off and the entire device is moved to the next tube in the waterwall.

Methods are described for the use of conformable eddy-current sensors and sensor arrays for characterizing residual stresses and applied loads in materials. In addition, for magnetizable materials such as steels, these methods can be used to determine carbide content and to inspect for grinding burn damage. The sensor arrays can be mounted inside or scanned across the inner surface of test articles and hollow fasteners to monitor stress distributions. A technique for placing eddy-current coils around magnetizable fasteners for load distribution monitoring is also disclosed.