WO2006003639A1 - Dispositif a magnetoresistance - Google Patents

Dispositif a magnetoresistance Download PDF

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Publication number
WO2006003639A1
WO2006003639A1 PCT/IE2004/000093 IE2004000093W WO2006003639A1 WO 2006003639 A1 WO2006003639 A1 WO 2006003639A1 IE 2004000093 W IE2004000093 W IE 2004000093W WO 2006003639 A1 WO2006003639 A1 WO 2006003639A1
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WO
WIPO (PCT)
Prior art keywords
magnetic
dielectric layer
electrode layers
tmr
ferromagnetic
Prior art date
Application number
PCT/IE2004/000093
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English (en)
Inventor
Igor Shvets
Original Assignee
The Provost Fellows And Scholars Of The College Of The Holy And Undivided Trinity Of Queen Elizabeth Near Dublin
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by The Provost Fellows And Scholars Of The College Of The Holy And Undivided Trinity Of Queen Elizabeth Near Dublin filed Critical The Provost Fellows And Scholars Of The College Of The Holy And Undivided Trinity Of Queen Elizabeth Near Dublin
Priority to PCT/IE2004/000093 priority Critical patent/WO2006003639A1/fr
Publication of WO2006003639A1 publication Critical patent/WO2006003639A1/fr

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F10/00—Thin magnetic films, e.g. of one-domain structure
    • H01F10/32—Spin-exchange-coupled multilayers, e.g. nanostructured superlattices
    • H01F10/324—Exchange coupling of magnetic film pairs via a very thin non-magnetic spacer, e.g. by exchange with conduction electrons of the spacer
    • H01F10/3254—Exchange coupling of magnetic film pairs via a very thin non-magnetic spacer, e.g. by exchange with conduction electrons of the spacer the spacer being semiconducting or insulating, e.g. for spin tunnel junction [STJ]
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B82—NANOTECHNOLOGY
    • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y25/00—Nanomagnetism, e.g. magnetoimpedance, anisotropic magnetoresistance, giant magnetoresistance or tunneling magnetoresistance
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F10/00—Thin magnetic films, e.g. of one-domain structure
    • H01F10/32—Spin-exchange-coupled multilayers, e.g. nanostructured superlattices
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N50/00—Galvanomagnetic devices
    • H10N50/10—Magnetoresistive devices

Definitions

  • the present invention relates to a tunnel magnetoresistance (TMR) device comprising a film laminate having two electrode layers separated by a thin dielectric layer for reception of electric current directed substantially orthogonal to one of the major exposed surfaces thereof.
  • TMR tunnel magnetoresistance
  • These devices are sometimes called simply “magnetoresistance devices” or “tunnel magnetoresistance devices”.
  • the current flowing between the two electrodes of the magnetoresistive device is sensitive to the external magnetic field.
  • a TMR should be so constructed whereby the resistance of the device can be switched by the current or voltage pulse.
  • Magnetoresistance devices of many different types are widely used in information and communication technologies e.g. in disk drive read heads, magnetic tape read heads, random access memory devices and in numerous other applications.
  • the typical role of the magnetoresistance device could be described as a sensor of the magnetic field created by the magnetic area storing information. Therefore, in this application the magnetoresistance device and the magnetic area storing information as well as, means for remagnetising, the magnetic area forms the foundations of the memory cell.
  • one random access memory chip contains many thousands of memory cells.
  • Magnetoresistance devices are also commonly used as sensors for a magnetic field in applications that are not directly related to the domain of information and communication technologies, e.g. in automotive and aviation industries, security devices, position encoders, medical devices and numerous other applications.
  • a magnetoresistance device typically it is desirable to have the device providing a large current (voltage or resistance) change in response to the magnetic field. In practice for many applications the resistance change of about 5-20% in a field of approximately 0.01 T or 0.1 T is considered acceptable.
  • the time response of the device is important, for example, for read heads of disk drives. The read head of the disk drive should be able to collect data at the speed of many Megabits/sec and even greater. Therefore, for this application the magnetoresistance device should be able to respond to a sudden change in the magnetic field within the time interval 10 '7 sec or shorter. For some applications it is important to have the resistance of the device within a certain range of values.
  • the resistance of the device preferably should not be very small by comparison to the resistance of the wires that connect it to the electric circuit.
  • the resistance should not be very large to make signal coupling from the device into an amplifier more efficient.
  • tunnelling magnetoresistance There are several classes of magnetoresistance devices. This invention is most closely related to the class of tunnel magnetoresistance devices that are based on spin-polarized electron tunnelling through a thin dielectric barrier known as tunnelling magnetoresistance (TMR).
  • TMR tunnelling magnetoresistance
  • the theoretical foundations for these devices have been laid some time ago although their practical implementation commenced during the last decade.
  • the phenomenon is based on the tunnel junction with two ferromagnetic electrodes.
  • the tunnel current between the electrodes depends on their relative orientation of magnetisations with respect to each other [M. Julliere, Phys. Lett. 54A, 225 (1975); J. Slonczewski, Phys. Rev. B 39, 6995 (1989)].
  • US Patent Specification No 5,835,314 further suggests that the greatest magnetoresistance effect is obtained when the tunnelling resistance of the device is comparable to the electrode resistance.
  • US Patent Specifications Nos 5,734,605 and 5,978,257 describe a tunnel junction element similar to the one described in US. Patent Specification No 5,629,922 and further teach how it could be utilised in a memory cell.
  • US Patent Specification No 6,335,081 (ArakJ et al) describes an improved tunnel magnetoresistance effect element based on a tunnel multilayered film with a tunnel barrier having reduced roughness of the layers. In most magnetic tunnel junction devices magnetisation of one of the two ferromagnetic layers is pinned by exchange coupling to an antiferromagnetic layer.
  • a related US Patent Specification No 6,069,820 also describes the spin dependent conduction device based on electron tunnelling in a multilayer system involving three or more metal electrodes. As in other inventions, nonmagnetic dielectric layers separate these magnetic conducting electrodes.
  • the US Patent Specification No 6,069,820 further describes the embodiments where some of the intermediate layers comprise the conducting particles of magnetic material embedded in a matrix of nonmagnetic dielectric to achieve some type of resonance tunnelling. This approach was further developed in the US Patent Specification No 6,114,056 (Inomata et al).
  • This patent also describes structures comprising of three ferromagnetic layers: ferromagnetic metal layer, ferromagnetic-dielectric layer and again ferromagnetic metal layer all separated from each other by nonmagnetic dielectric layers. It will be noted that these US Patents 6,069,820, 6,114,056 and 6,365,286 all have one inventor in common.
  • the electrodes are made of common transition metals and their alloys, e.g. Fe, Ni, Co, permaloy. The reason is that although these materials have lower spin polarisation, they are more technology-friendly and the films of these materials have more consistent properties.
  • spin-dependent current can be achieved in the case of tunnelling between an antiferromaghetic electrode and a ferromagnetic one across a nonmagnetic dielectric barrier.
  • the tunnel current is sensitive to the direction of magnetisation in the ferromagnetic electrode with respect to the antiferromagnetic direction of the other electrode [A.A. Minakov, IV. Shvets, Surf Sci. 236 (1990) L377-L-381].
  • This sensitivity was recently used to achieve spin dependent imaging with STM on the atomic scale whereby an antiferromagnetic MnNi tip was used instead of a conventional tungsten tip [N.Berdunov, S. Murphy, G. Mariotto, I.V. Shvets, Phys Rev. Lett, to be published; G. Mariotto, S.Murphy, I.V. Shvets Phys.Rev.B 66 245426 (2002)].
  • the present invention is directed towards providing an improved tunnel magnetoresistance -(TMR) device which will overcome certain of the problems with known TMR's and which will additionally provide a TMR whereby the resistance of the device can be switched by a current or voltage pulse. Further, the invention is directed towards providing an improved construction of such TMR.
  • TMR tunnel magnetoresistance -
  • Another objective of the present invention is directed towards providing a multi-stable switch, i.e. the resistive element whose resistance can be altered by a voltage or a current pulse.
  • tunnel magneioresistance (TMR) device comprising:
  • the advantage of the present invention over a conventional TMR device is that the resistance change does not occur solely in response to the change in magnetisation direction of one electrode with respect to the other.
  • the change in magnetoresistance occurs even when both electrode layers have the same direction of magnetisation.
  • the resistance to change is not proportional to the spin polarisation of each of the electrode layers.
  • an advantage of the present invention is that the performance of the device is based on the alteration of the height of the tunnel barrier which alters the barrier transparency.
  • both electrodes are of a magnetic material.
  • both electrode layers have the same direction of magnetisation or in another embodiment, the electrode layers have different directions of magnetisation.
  • the advantage of the latter is that the effect of spin polarisation can also be used with the present invention.
  • the electrode layers are of a material having a relatively high degree of spin polarisation.
  • At least one of the electrode layers is of a ferromagnetic material, as is the dielectric layer.
  • At least one of the electrode layers is of a ferromagnetic material and the other dielectric layer is of an anti-ferromagnetic material.
  • At least one of the electrode layers is of an anti- ferromagnetic material and the other dielectric layer is of a ferromagnetic material.
  • one of the electrode layers is of a non-magnetic material.
  • the dielectric layer is a composite tunnel barrier layer comprising a laminate of a magnetic layer, sandwiched between two non-magnetic layers or alternatively it is a sandwich of a magnetic layer and a nonmagnetic layer.
  • the dielectric layer is a composite tunnel barrier layer comprising a laminate of a non-magnetic layer, sandwiched between two magnetic layers.
  • the dielectric layer is a laminate of non-magnetic dielectric material on a magnetic material in which the non-magnetic material is one of:
  • the anti-ferromagnetic material is one of:
  • Ci-Fe 2 O 3 a sulphate, a transition metal oxide, and a selenide.
  • the material and thickness of the dielectric layer is chosen to have a resistance not greater than 10 8 ⁇ per ⁇ m 2 .
  • the electrode layers may be of a ferromagnetic spinel oxide.
  • the thickness of the dielectric layer is between 0.2 and 20 nm.
  • a multi-stable switch in which there are two magnetic electrode layers, the magnetisation of one of the electrode layers being pinned.
  • the electrode layers are of a ferromagnetic material.
  • the direction of the magnetisation of the electrode layers is so chosen as to be different to provide a device, the operation of which mirrors that of a magnetic diode.
  • means are provided to alter one of the magnetisations of each magnetic electrode layer and the dielectric layer.
  • the material of the dielectric layer is so chosen that the sensitivity to the magnetic field of the device is based on the dependency of the height of the tunnel barrier resulting from exchange interaction of tunnelling electrons emitted by one of the electrode layers with electrons of the tunnel barrier.
  • the direction of spins within the dielectric layer can be altered by the voltage or current pulse between the two electrode layers.
  • Figs. 1 to 6 are schematic cross-sectional views of various tunnel magnetoresistance (TMR) devices according to the invention.
  • connection wires and elements of the circuitry and circuit infrastructure that is required to form a functioning sensor or to integrate the sensor into the memory cell.
  • These elements are common in the state-of-the-art and therefore are known to those skilled in magnetic tunnel junctions.
  • none of the embodiments illustrate substrate, seed layers, buffer layer, protection layer, exchange bias layer and other layers that are typically added in the stack of a magnetic tunnel junction. In a typical stack of magnetic tunnel junction, one could count up to 10 or 20 different layers. The use of these layers is known to specialists in the field and the specific arrangement depends on the specific application of the device, the materials and the fabrication processes used. In order to focus the attention of the fundamentals of the invention we have shown just the key functional layers.
  • ferrimagnetic includes both notions as commonly known to those skilled in the art of magnetism, namely, ferromagnetic and ferrimagnetic. It should be appreciated that although no distinction between the two is often made, strictly speaking they relate to two different classes of materials. Ferrimagnetic is related to materials having more than one magnetic sub-lattice and having net magnetic moment. For example, the material Fe 3 O 4 that is often referred to as being ferromagnetic, is in fact ferrimagnetic. Therefore, for the purposes of this invention we do not make any distinction between the two.
  • magnetic is used to encompass any of the three: “ferromagnetic”, “ferrimagnetic” and “antiferromagnetic”.
  • antiferromagnetic is used as known to specialists in the field and means magnetic material with more than one magnetic sub-lattice and effectively no net magnetic moment.
  • a tunnel magnetoresistance device comprising two ferromagnetic layers 2 and 3, sandwiching therebetween a further ferromagnetic dielectric layer 4.
  • the term "electrode layer” and “electrode” and similarly “dielectric layer” and “dielectric” are used somewhat interchangeably, since the electrode layer forms an electrode.
  • the direction of magnetisation in the electrodes and in the electrode layers 2 and 3, and in the dielectric layer or barrier 4 are identified by the arrow M and appropriate subscripts.
  • the electrode layers 2, 3 are characterised by a hicjh degree of spin polarisation at the Fermi level.
  • magnetisations M 2 and M 3 in both electrodes have the same direction.
  • the tunnel barrier is composed of a ferromagnetic dielectric material. This could be one of the ferromagnetic oxides e.g.
  • the dielectric layer should preferably be uniform and free from pinholes, i.e. the two electrodes should not be in direct electric contact with each other.
  • the direction of magnetisation M 4 in the barrier is different from the direction of magnetisations M 2 and M 3 in the electrodes . It appears that the tunnel current between the two ferromagnetic electrodes depends on the relative direction of the spin of electrons emitted by the electrodes with respect to the magnetisation in the tunnel barrier. The reason is that the tunnelling electrons see interaction with the spins of the dielectric layer through additional exchange energy /2 are electron spins in the first electrode and barrier respectively. This additional energy either increases or decreases the effective tunnel barrier depending on the relative direction of spins in the electrodes and the ferromagnetic layer. Therefore, the tunnel current at low bias voltage V is
  • TMR tunnel magnetoresistance
  • the resistance change is proportional to the spin polarisation of each of the electrodes. This is well explained in the previously referenced paper [J. Slonczewski, Phys. Rev. B 39, 6995 (1989)]. Therefore, if the second electrode has zero spin polarisation, the conventional TMR device has no sensitivity to the magnetic field. In the present invention, the device will have sensitivity to a magnetic field even if the spin polarisation of the second electrode is zero.
  • the dielectric barrier is nonmagnetic. In the present invention, it is magnetic.
  • the spin polarisation of the dielectric barrier cannot be defined in the conventional sense of the definition of spin polarisation. Indeed a dielectric material has no electrons in both spin up and spin down bands at the Fermi level meaning that the spin polarisation would be calculated as the ratio of zero to zero, i.e. mathematical nonsense. iv).
  • the performance of the device is based on the alteration of the height of the tunnel barrier which alters the barrier transparency.
  • the barrier is kept constant and the effect is based on the control of the electron density of the electrons capable of performing tunnelling to the empty states of the second electrode.
  • Fig. 2 there is illustrated an alternative tunnel magnetoresistance device, again indicated generally by the reference numeral 2, in which parts similar to those described with reference to the previous drawings are identified by the same reference numerals.
  • the electrode layers 2 and 3 are of a ferromagnetic material, however, the dielectric layer 2, that is to say, the dielectric barrier, is of an anti-ferromagnetic dielectric material.
  • the dielectric layer preferably should not contain pin-holes, which, as it will be appreciated by those skilled in the art, is required to ensure that the two electrodes are not in contact with each other.
  • the thickness range of the antiferromagnetic dielectric barrier is comparable to the one indicated for the ferromagnetic barrier with reference to Fig, 1. In the same way as with the case of a ferromagnetic dielectric barrier, the exchange interaction should appear in the Hamiltonian for the barrier region and with it in the tunnelling.
  • the spin operator of barrier electrons S b is replaced by the antiferromagnetic operator l_ b and the angular dependency of the current on the direction of magnetisation in the ferromagnetic electrode should reflect the symmetry of the antiferromagnetic material.
  • the rotation of magnetisation M 2 by % with respect to the antiferromagnetic direction A of the dielectric layer should not alter the current because of the symmetry considerations, whereas, rotation by ⁇ /2 should.
  • This is similar to the angular dependency in the tunnel junction consisting of one ferromagnetic and one antiferromagnetic electrodes separated by a nonmagnetic dielectric layer, as previously referenced, [A.A. Minakov, I.V. Shvets, Surf. Sci.
  • the TMR device with both electrodes of antiferromagnetic material and a ferromagnetic dielectric layer.
  • k ⁇ .m ⁇ I % and ⁇ b is the wave function of the electrons in the dielectric layer.
  • H is the Hamiltonian.
  • the exchange constant can be calculated using the simplified formula
  • the dielectric layer 4 comprises a laminate, namely, a non ⁇ magnetic dielectric layer 4(a) and a magnetic dielectric layer 4(b), in this embodiment of a ferromagnetic material. Both of the electrodes 2 and 3 are of a ferromagnetic material. Essentially, the dielectric layer 4 is formed by depositing a layer of conventional nonmagnetic dielectric material on top of a layer of magnetic material.
  • MgO or MgAI 2 O 4 , AI 2 O 3 , SrTiO 3 indeed another suitable nonmagnetic dielectric layer.
  • the electrode layer 2 is of a non-magnetic material, while the electrode layer 3 is of a magnetic material, sandwiching therebetween a ferromagnetic dielectric layer 4.
  • the embodiment operates in much the same way as the embodiment described with reference to Fig. 1.
  • the concept of the spin sensitivity is based on the dependency of the transparency of the tunnel barrier on the relative directions of the magnetisations in the magnetic electrode and the dielectric magnetic layer.
  • a further TMR device again indicated generally by the reference numeral 1 , and is substantially similar to the device illustrated in Fig. 2, except now one of the electrode layers 2 is of a non-magnetic material.
  • the dielectric layer 4 is of a anti-ferromagnetic material.
  • the tunnel barrier or dielectric layer 4 is composed of at least two layers. One of them is a magnetic layer 4(a) and the other one is a dielectric layer 4(b) that is deposited to seal the pin-holes in the magnetic dielectric layer.
  • the construction of this tunnel barrier 4 is similar to the one described with reference to Fig. 3.
  • the magnetic dielectric layer could be deposited first and a nonmagnetic layer on top or vice versa.
  • a composite barrier consisting of more than two layers.
  • the barrier could comprise of a magnetic dielectric layer sandwiched between two nonmagnetic dielectric layers or vice versa: a nonmagnetic dielectric layer interposed between two magnetic dielectric layers.
  • Other cases with more than three layers can be constructed as well.
  • the current in the device depends on the polarity of the bias voltage applied to it. This is very different from the conventional TMR device of two ferromagnetic electrodes separated by a nonmagnetic dielectric.
  • the tunnel current depends on the product of spin polarisations P 2 and P 3 of the two electrodes and also on the angle between the magnetisation directions of the electrodes. When the current direction is reversed the resistance of the junction is not affected.
  • the value of the voltage drop across the device is altered when the direction of the current through it is reversed.
  • the device shown in Figs 4,5,6, effectively forms a magnetic diode, i.e. it is a diode as its I-V curve is asymmetric and furthermore the I-V curve can be controlled by altering the magnetisation of the magnetic electrode or the dielectric layer.
  • magnetic moment of a ferromagnetic layer can be altered by current of spin-polarised electrons injected into the layer. This has been predicted theoretically in [Slonczewski J. C, Journal of Magn. Magn. Mater. 159 (1- 2) L1-L7 (1996)]. Yet, more experimental evidence needs to be collected to understand if and how this effect could be used to alter magnetisation in real systems. For example there are active efforts by many research groups to demonstrate a multistable switch based on magnetic tunnel junction. In this approach magnetisation of one of the ferromagnetic electrodes is pinned and the magnetisation of the second electrode is expected to be altered from one stable state to the other one when current pulse is applied between the two electrodes. It is envisaged that the same approach could be used in the case of the device described in the present invention.
  • the invention is not limited by the accuracy of the formulas (1-5).
  • the formulas (1-5) are given here merely to explain the essence of the invention rather than be used as a quantitative guide. It is expected that the accuracy of the formulas depends on the detailed model used to describe different aspects on the tunnelling process and physics of exchange interaction. This will be apparent to those skilled in this technology.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Power Engineering (AREA)
  • Nanotechnology (AREA)
  • Semiconductor Memories (AREA)
  • Hall/Mr Elements (AREA)

Abstract

L'invention concerne un dispositif à magnétorésistance tunnel (TMR). On a décrit uniquement les couches auxiliaires d'un tel dispositif, lequel comprend un film stratifié ayant deux couches d'électrode (2, 3) séparées par une couche diélectrique mince recevant un courant électrique de direction sensiblement orthogonale à l'une des surfaces principales exposées (5, 6) du dispositif (1). Au moins l'une des couches électrodes (2, 3) est en un matériau magnétique et, contrairement à la technique connue, la couche diélectrique est une couche en un matériau magnétique, un stratifié d'un matériau ferromagnétique ou anti-ferromagnétique, ou bien, peut être un stratifié d'un matériau diélectrique non magnétique sur un matériau magnétique. Le dispositif ne dépend pas du changement dans la direction de magnétisation d'une électrode (2) par rapport à l'autre électrode (3). En fait, ces deux électrodes (2, 3) peuvent avoir sensiblement la même direction de magnétisation, mais il n'est pas essentiel qu'il en soit ainsi.
PCT/IE2004/000093 2004-07-01 2004-07-01 Dispositif a magnetoresistance WO2006003639A1 (fr)

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Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2452093A (en) * 2007-08-21 2009-02-25 Western Lights Semiconductor Co Apparatus for Storing Electrical Energy
EP2109123A1 (fr) * 2008-04-11 2009-10-14 Northern Lights Semiconductor Corp. Appareil de stockage d'énergie électrique
EP2421063A1 (fr) * 2009-04-16 2012-02-22 National Institute for Materials Science Structure de jonction tunnel ferromagnétique, et élément à effet magnétorésistif et dispositif spintronique comprenant chacun cette structure
EP2744002A1 (fr) * 2012-12-14 2014-06-18 Hitachi Ltd. Dispositif de mémoire
US10238512B2 (en) * 2013-02-22 2019-03-26 Cardiatis S.A. MRI visible medical device

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EP0877398A2 (fr) * 1997-05-09 1998-11-11 Kabushiki Kaisha Toshiba Elément magnétique et tête magnétique ou élément de mémoire utilisants cet élément
US6069820A (en) * 1998-02-20 2000-05-30 Kabushiki Kaisha Toshiba Spin dependent conduction device
US6365286B1 (en) * 1998-09-11 2002-04-02 Kabushiki Kaisha Toshiba Magnetic element, magnetic memory device, magnetoresistance effect head, and magnetic storage system
US20020097534A1 (en) * 2000-11-17 2002-07-25 Tdk Corporation Magnetic tunnel junction read head devices having a tunneling barrier formed by multi-layer, multi-oxidation processes
US20020154456A1 (en) * 2001-04-24 2002-10-24 Carey Matthew Joseph Stability-enhancing underlayer for exchange-coupled magnetic structures, magnetoresistive sensors, and magnetic disk drive systems
EP1320104A1 (fr) * 2001-12-13 2003-06-18 Kabushiki Kaisha Toshiba Dispositif de mémoire magnétique et procédé de fabrication associé

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0877398A2 (fr) * 1997-05-09 1998-11-11 Kabushiki Kaisha Toshiba Elément magnétique et tête magnétique ou élément de mémoire utilisants cet élément
US6069820A (en) * 1998-02-20 2000-05-30 Kabushiki Kaisha Toshiba Spin dependent conduction device
US6365286B1 (en) * 1998-09-11 2002-04-02 Kabushiki Kaisha Toshiba Magnetic element, magnetic memory device, magnetoresistance effect head, and magnetic storage system
US20020097534A1 (en) * 2000-11-17 2002-07-25 Tdk Corporation Magnetic tunnel junction read head devices having a tunneling barrier formed by multi-layer, multi-oxidation processes
US20020154456A1 (en) * 2001-04-24 2002-10-24 Carey Matthew Joseph Stability-enhancing underlayer for exchange-coupled magnetic structures, magnetoresistive sensors, and magnetic disk drive systems
EP1320104A1 (fr) * 2001-12-13 2003-06-18 Kabushiki Kaisha Toshiba Dispositif de mémoire magnétique et procédé de fabrication associé

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2452093A (en) * 2007-08-21 2009-02-25 Western Lights Semiconductor Co Apparatus for Storing Electrical Energy
GB2452093B (en) * 2007-08-21 2009-07-29 Western Lights Semiconductor Corp Apparatus for storing electrical energy
EP2109123A1 (fr) * 2008-04-11 2009-10-14 Northern Lights Semiconductor Corp. Appareil de stockage d'énergie électrique
EP2421063A1 (fr) * 2009-04-16 2012-02-22 National Institute for Materials Science Structure de jonction tunnel ferromagnétique, et élément à effet magnétorésistif et dispositif spintronique comprenant chacun cette structure
US20120091548A1 (en) * 2009-04-16 2012-04-19 Hiroaki Sukegawa Ferromagnetic tunnel junction structure, and magneto-resistive element and spintronics device each using same
EP2421063A4 (fr) * 2009-04-16 2013-03-27 Nat Inst For Materials Science Structure de jonction tunnel ferromagnétique, et élément à effet magnétorésistif et dispositif spintronique comprenant chacun cette structure
US8575674B2 (en) * 2009-04-16 2013-11-05 National Institute For Materials Science Ferromagnetic tunnel junction structure, and magneto-resistive element and spintronics device each using same
EP2744002A1 (fr) * 2012-12-14 2014-06-18 Hitachi Ltd. Dispositif de mémoire
US10238512B2 (en) * 2013-02-22 2019-03-26 Cardiatis S.A. MRI visible medical device

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