5577 results about "Nuclear magnetic resonance" patented technology

Method and apparatus for determining the instantaneous location, the orientation of an object moving through a three-dimensional space by applying to the object a coil assembly including a plurality of sensor coils (20) having axes of known orientation with respect to each other including components in the three orthogonal planes; generating a time-varying, three-dimensional magnetic field gradient having known instantaneous values of magnitude and direction; applying the magnetic field gradient to the space, and object moving therethrough to induce electrical potentials in the sensor coils; measuring the instantaneous values of the induced electrical potentials generated in the sensor coils; processing the measured instantaneous values generated in the sensor coils together with the known magnitude, direction of the generated magnetic field gradient, the known relative orientation of the sensor coils in the coil assembly to compute the instantaneous location, orientation of the object within the space.

A magnetic memory cell and a magnetic memory incorporating the cell are described. The magnetic memory cell includes at least one magnetic element and at least one non-planar selection device. The magnetic element(s) are programmable using write current(s) driven through the magnetic element. The magnetic memory may include a plurality of magnetic storage cells, a plurality of bit lines corresponding to the plurality of magnetic storage cells, and a plurality of source lines corresponding to the plurality of magnetic storage cells.

A magnetic element is disclosed that has a composite free layer with a FM1/moment diluting/FM2 configuration wherein FM1 and FM2 are magnetic layers made of one or more of Co, Fe, Ni, and B and the moment diluting layer is used to reduce the perpendicular demagnetizing field. As a result, lower resistance x area product and higher thermal stability are realized when perpendicular surface anisotropy dominates shape anisotropy to give a magnetization perpendicular to the planes of the FM1, FM2 layers. The moment diluting layer may be a non-magnetic metal like Ta or a CoFe alloy with a doped non-magnetic metal. A perpendicular Hk enhancing layer interfaces with the FM2 layer and may be an oxide to increase the perpendicular anisotropy field in the FM2 layer. The magnetic element may be part of a spintronic device or serve as a propagation medium in a domain wall motion device.

A method and system for providing a magnetic element and memory utilizing the magnetic element are described. The magnetic element includes a reference layer, a nonferromagnetic spacer layer, and a free layer. The reference layer has a resettable magnetization that is set in a selected direction by a magnetic field generated externally to the reference layer. The reference layer is also magnetically thermally unstable at an operating temperature range and has KuV/kBT is less than fifty five. The spacer layer resides between the reference layer and the free layer. In addition, the magnetic element is configured to allow the free layer to be switched to each of a plurality of states when a write current is passed through the magnetic element.

A method of slice selective multiple quantum magnetic resonance imaging of an object is disclosed. The method is effected by implementing the steps of (a) applying a radiofrequency pulse sequence selected so as to select a coherence of an order n to the object, wherein n is zero, a positive or a negative integer other than ±1; (b) applying magnetic gradient pulses, so as to select a slice of the object to be imaged arid to create an image; and (c) acquiring a radiofrequency signal resulting from the object, so as to generate a magnetic resonance slice image of the object. The method provides slice selective multiple quantum magnetic resonance images of yet unprecedented quality in terms of contrast. The method is particularly useful for imaging connective tissues.

A magnetic memory element switchable by current injection includes a plurality of magnetic layers, at least one of the plurality of magnetic layers having a perpendicular magnetic anisotropy component and including a current-switchable magnetic moment, and at least one barrier layer formed adjacent to the plurality of magnetic layers (e.g., between two of the magnetic layers). The memory element has the switching threshold current and device impedance suitable for integration with complementary metal oxide semiconductor (CMOS) integrated circuits.

A magnetic induction (MI) repeater includes first and second coils configured to have the same resonance frequency and to be substantially isolated from one another, and an amplifier connected to the first and second coils and configured to receive a signal induced in the first coil by a first magnetic field and output, via the second coil, a second magnetic field based on the signal, wherein the second magnetic field is amplified relative to the first magnetic field.

With a view toward implementing a thermal controlling method for making reversible a temperature characteristic of a magnetic field generator using permanent magnets small in Hcj, a magnetic field generator whose temperature characteristic is reversible, using permanent magnets small in Hcj, and an MRI apparatus provided with such a magnetic field generator, there is provided a method for controlling the temperature of a magnetic field generator having a pair of disc-shaped permanent magnets whose magnetic poles opposite in polarity to each other are opposed to each other with spacing defined therebetween, and a yoke that forms return passes for magnetic fluxes of the permanent magnets, comprising the steps of raising the temperature from room temperature to a temperature higher than the room temperature, maintaining the temperature higher than the room temperature, and lowering the temperature from the temperature higher than the room temperature to the room temperature, whereby the temperature characteristics of the permanent magnets are made reversible.

A magnetic element is disclosed wherein first and second interfaces of a free layer with a Hk enhancing layer and tunnel barrier, respectively, produce enhanced surface perpendicular anisotropy to lower switching current or increase thermal stability in a magnetic tunnel junction (MTJ). In a MTJ with a bottom spin valve configuration where the Hk enhancing layer is an oxide, the capping layer contacting the Hk enhancing layer is selected to have a free energy of oxide formation substantially greater than that of the oxide. The free layer may be a single layer or composite comprised of an Fe rich alloy such as Co₂₀Fe₆₀B₂₀. With a thin free layer, the interfacial perpendicular anisotropy may dominate the shape anisotropy to generate a magnetization perpendicular to the planes of the layers. The magnetic element may be part of a spintronic device or serve as a propagation medium in a domain wall motion device.

A compact sensor for detection of chemical and/or biological compounds in low concentration. The sensor comprises electromagnetic microcavities. The agent to be detected passes the microcavities, is absorbed and/or absorbed by the microcavities, and modifies the electromagnetic field inside the microcavities. After the agent has been adsorbed and/or absorbed, a probe beam is applied to the microcavities. The change of electromagnetic field is detected by the detector, and the frequency of the probe beam at which the resonance is observed, is indicative of a particular agent being present. A method for detecting chemical and/or biological compounds using the sensor.

A combination MRI and radiotherapy system comprising: a) an MRI system for imaging a patient receiving radiotherapy, comprising a magnetic field source suitable for generating a magnetic field of strength and uniformity useable for imaging, capable of being ramped up to said magnetic field in less than 10 minutes, and ramped down from said magnetic field in less than 10 minutes; b) a radiation source configured for applying radiotherapy; and c) a controller which ramps the magnetic field source down to less than 20% of said magnetic field strength when the radiation source is to be used for radiotherapy, and ramps the magnetic field source up to said magnetic field strength when the MRI system is to be used for imaging.

Apparatus for detecting a metal object comprises a transmitter for generating a pulsed or an alternating magnetic field in the vicinity of the metal object to be detected and a detector for detecting the secondary magnetic field induced in the metal object by the transmitted magnetic field. The detector measures at least three magnetic field gradient components of at least first order of the secondary magnetic field. The apparatus also comprises a processor for determining at least one of the position or the electro-magnetic cross-section or an estimate of the shape of the metal object from the measured magnetic field spatial gradient components. The processor fits the measured components to dipole, multiple dipole, multipole, or extended source models. In a preferred embodiment, the invention may comprise three or more pairs of gradiometric coils, or other sensing means. The detector measures at least five magnetic field gradient components of at least first order, and one or more components of the secondary magnetic field. The detector may be coils, or any other magnetic sensors. The processor enters pre-determined criteria to discriminate against detection of metal objects of no interest or to selectively detect metal objects of interest.

A method and system for providing a magnetic element and a magnetic memory utilizing the magnetic element are described. The magnetic element is used in a magnetic device that includes a contact electrically coupled to the magnetic element. The method and system include providing pinned, nonmagnetic spacer, and free layers. The free layer has an out-of-plane demagnetization energy and a perpendicular magnetic anisotropy corresponding to a perpendicular anisotropy energy that is less than the out-of-plane demagnetization energy. The nonmagnetic spacer layer is between the pinned and free layers. The method and system also include providing a perpendicular capping layer adjoining the free layer and the contact. The perpendicular capping layer induces at least part of the perpendicular magnetic anisotropy in the free layer. The magnetic element is configured to allow the free layer to be switched between magnetic states when a write current is passed through the magnetic element.

A MTJ for a spintronic device is disclosed and includes a thin composite seed layer made of at least Ta and a metal layer having fcc(111) or hcp(001) texture as in Ta/Ti/Cu to enhance perpendicular magnetic anisotropy (PMA) in an overlying laminated layer with a (CoFe/Ni)_X, (Co/NiFe)_X, (Co/NiCo)_X, (CoFe/NiFe)_X, or (CoFe/NiCo)_X composition where x is from 5 to 30. In one embodiment, a CPP-TMR spin valve has one or both of a laminated free layer and laminated reference layer with the aforementioned compositions. The MTJ includes an interfacial layer made of CoFeB, CoFeB/CoFe, or CoFe/CoFeB between each laminated structure and the tunnel barrier. The laminated layers are deposited by a low power and high Ar pressure process to avoid damaging interfaces between adjoining layers. Annealing occurs at 220° C. to 400° C. A laminated layer with high PMA may also be included in one or more layers of a spin transfer oscillator.

A magnetic memory cell having a ferromagnetic free layer and a ferromagnetic pinned reference layer, each having an out-of-plane magnetic anisotropy and an out-of-plane magnetization orientation and switchable by spin torque. The cell includes a ferromagnetic assist layer proximate the free layer, the assist layer having a low magnetic anisotropy less than about 500 Oe. The assist layer may have in-plane or out-of-plane anisotropy.

A high-frequency oscillation element has a ferromagnetic material which exhibits thermal fluctuation of magnetization and generates spin fluctuations in conduction electrons, a nonmagnetic conductive material which is laminated on the first magnetic material and transfers the conduction electrons, a magnetic material which is laminated on the nonmagnetic conductive material, generates magnetic resonance upon injection of the conduction electrons, and imparts magnetic dipole interaction to magnetization of a neighboring magnetic area by means of magnetic vibration stemming from the magnetic resonance, a first electrode electrically coupled with the first magnetic material, and a second electrode electrically coupled with the second magnetic material.

A method of testing P2 stiffness of a magnetoresistance (MR) sensor stack including a P2 pinned layer is provided. The method comprises the step of applying an external magnetic field to the MR sensor stack. The external magnetic field is oriented substantially perpendicular to a magnetic field of the P2 pinned layer. The method further comprises varying an amplitude of the external magnetic field, measuring a change in a resistance of the MR sensor stack in response to the varying amplitude of the external magnetic field, and calculating the P2 stiffness based on the measured change in resistance.

A two-axis magnetic field sensor includes a substrate, a first sensor having at least one magnetoresistive element formed of GMR material on the substrate has a free layer having an easy axis of effective anisotropy field in a first direction. The first sensor is sensitive to magnetic field components perpendicular to the first direction. A current is caused to flow through the first sensor and variations in the resistivity of the first sensor due to the first magnetic field components are sensed. A second sensor having at least one magnetoresistive element formed of GMR material on the substrate has a free layer having an easy axis of effective anisotropy field in a direction substantially perpendicular to the first direction. The second sensor is sensitive to second magnetic field components perpendicular to its easy axis of effective anisotropy. A current is caused to flow through the second sensor and variations in the resistivity of the second sensor due to second magnetic field components are sensed.

A method and apparatus of a spin-type magnetoresistance sensor having a free and pinned magnetic layer stacked with a non-magnetic interposed layer are disclosed. Specifically, the spin-valve type magnetoresistance sensor of the present invention is equipped with a free ferromagnetic layer, a pinned ferromagnetic layer, a non-magnetic spacer layer which is sandwiched between the aforementioned ferromagnetic layers, an anti-ferromagnetic layer which is disposed adjacent to the aforementioned pinned ferromagnetic layer and which is used to pin the direction of magnetization of said pinned ferromagnetic layer, a non-magnetic back layer which is disposed adjacent to the aforementioned free ferromagnetic layer and which is stacked on the opposite side the free ferromagnetic layer from the aforementioned nonmagnetic spacer layer, and an electron-reflective layer which is disposed adjacent to the aforementioned back layer and which is stacked on the opposite side of the back layer from the aforementioned free ferromagnetic layer.

A memory cell including information that is stored in the state of a magnetic bit (i.e. in a free layer, FL), where the FL magnetization has two stable states that may be canted (form an angle) with respect to the horizontal and vertical directions of the device is presented. The FL magnetization may be switched between the two canted states by the application of a voltage (i.e. electric field), which modifies the perpendicular magnetic anisotropy of the free layer.

A method and system for providing a magnetic element is described. The magnetic element includes a pinned layer, a spacer layer, and a free layer. The spacer layer is nonferromagnetic and resides between the pinned layer and the free layer. The free layer includes a first magnetic layer and at least one of a second magnetic layer and an intermediate layer. The intermediate layer would reside between the first and second magnetic layers. The free layer also includes at least one domain wall therein during switching. In addition, the magnetic element is configured to allow the free layer to be switched at least in part due to spin transfer when a write current is passed through the magnetic element.

It is possible to reduce a current required for spin injection writing. A magneto-resistance effect element includes: a first magnetization pinned layer; a magnetization free layer; a tunnel barrier layer; a second magnetization pinned layer whose direction of magnetization is pinned to be substantially anti-parallel to the direction of magnetization of the first magnetization pinned layer, and; a non-magnetic layer. When the second magnetization pinned layer is made of ferromagnetic material including Co, material for the non-magnetic layer is metal including at least one element selected from the group consisting of Zr, Hf, Rh, Ag, and Au; when the second magnetization pinned layer is made of ferromagnetic material including Fe, material for the non-magnetic layer is metal including at least one element selected from the group consisting of Rh, Pt, Ir, Al, Ag, and Au; and when the second magnetization pinned layer is made of ferromagnetic material including Ni, material for the non-magnetic layer is metal including at least one element selected from the group consisting of Zr, Hf, Au, and Ag.

The magnetic signal reproduction system comprises a magnetic recording medium comprising a magnetic layer comprising a ferromagnetic powder and a binder on a nonmagnetic support and a reproduction head, wherein a number of protrusions equal to or greater than 10 nm in height on the magnetic layer surface, as measured by an atomic force microscope, ranges from 50 to 2500/10,000 μm², a quantity of lubricant on the magnetic layer surface, denoted as a surface lubricant index, ranges from 0.5 to 5.0, a surface abrasive occupancy of the magnetic layer ranges from 2 to 20 percent, the reproduction head is a magnetoresistive magnetic head comprising a spin-valve layer, the spin-valve layer comprises a magnetization free layer, a magnetization pinned layer and an antiferromagnetic layer, and the antiferromagnetic layer is comprised of alloy comprising iridium and manganese, and the reproduction head comes in sliding contact with the magnetic recording medium during signal reproduction.

Techniques for ultrahigh density writing on an erasable magnetic medium include using a micromachined mechanism having two probes for writing to the medium. Use of the two probe embodiment eliminates the need to change the magnetic orientation of the probe. In another embodiment, a single probe is provided which is heated to the vicinity of its Curie temperature to enable the magnetic orientation of the probe to be switched. The probe may be heated to its Curie temperature through the use of a heating element or a focused laser. In another embodiment of the present invention, either the magnetic orientation of the probe or the magnetic orientation of the medium may be switched through the combination of a static magnetic field, a radio frequency magnetic field and, under certain circumstances, the magnetic field of the probe. In all cases, the writing techniques enable information to be written to a magnetic medium in a manner which enables the information to be erased and the medium rewritten.

A chirped pulse amplification system includes one or more polarization compensator configured to compensate for polarization altering elements with the chirped pulse amplification system. The polarization compensator is responsive to a sensor configured to provide feedback to the polarization compensator. In some embodiments, the chirped pulse amplification system further includes a controller configured to automatically adjust the polarization compensator responsive to the sensor. The sensor is optionally a power sensor.

The magnetic signal reproduction system comprises a magnetic recording medium comprising a magnetic layer comprising a ferromagnetic powder and a binder on a nonmagnetic support; and a reproduction head, wherein a number of protrusions equal to or greater than 10 nm in height on the magnetic layer surface, as measured by an atomic force microscope, ranges from 50 to 2500/10,000 μm², a quantity of lubricant on the magnetic layer surface, denoted as a surface lubricant index, ranges from 0.5 to 5.0, a surface abrasive occupancy of the magnetic layer ranges from 2 to 20 percent, and the reproduction head is a magnetoresistive magnetic head comprising a spin-valve layer.

A method and system for providing a magnetic element and a magnetic memory utilizing the magnetic element are described. The magnetic element is used in a magnetic device that includes a contact electrically coupled to the magnetic element. The method and system include providing pinned, nonmagnetic spacer, and free layers. The free layer has an out-of-plane demagnetization energy and a perpendicular magnetic anisotropy corresponding to a perpendicular anisotropy energy that is less than the out-of-plane demagnetization energy. The nonmagnetic spacer layer is between the pinned and free layers. The method and system also include providing a perpendicular capping layer adjoining the free layer and the contact. The perpendicular capping layer induces at least part of the perpendicular magnetic anisotropy in the free layer. The magnetic element is configured to allow the free layer to be switched between magnetic states when a write current is passed through the magnetic element.

A system for combining electromagnetic position and orientation tracking with magnetic resonance scanner is provided. One embodiment includes a magnetic resonance scanner defining a reference coordinate system for scanning a target. Coupled to the magnetic resonance scanner is a magnetic field source which produces a magnetic field. The magnetic field is sensed by a magnetic field sensor which produces a signal proportional to the magnetic field. The magnetic field sensor has a location relative to the reference coordinate system. The location of the magnetic field sensor relative to the reference coordinate system of the magnetic resonance scanner is determined by a location tracking device using at least a line segment model of the magnetic field source and the signal from the magnetic field sensor.

An apparatus and a method is provided based on the Magnetic Resonance techniques to analyze and measure a uni- and/or a bi-directional flow regime of multiphase fluids in a transport and production conduct, in real time and flow-rates, based on a magnetic resonance analytical module, two magnetic prepolarization modules of variable effective length and a control computer of data acquisition and transfer, all associated to each other.

A method and system for providing a magnetic element that can be used in a magnetic memory is disclosed. The magnetic element includes pinned, spacer, free, and spin barrier layers. The spacer layer is nonmagnetic and resides between the pinned and free layers. The free layer can be switched using spin transfer when a write current is passed through the magnetic element. The free layer resides between the spacer layer and the spin barrier layer. The spin barrier layer is configured to reduce an outer surface contribution to a damping constant of the free layer. In one aspect, the spin barrier layer has a high areal resistance and may substantially eliminate spin pumping induced damping. In another aspect, the magnetic element also includes a spin accumulation layer between the spin barrier and free layers. The spin accumulation layer has a high conductivity, preferably being metallic, and may have a long spin diffusion length.