EP0647323A1 - Magnetic field sensor - Google Patents

Magnetic field sensor

Info

Publication number
EP0647323A1
EP0647323A1 EP93913193A EP93913193A EP0647323A1 EP 0647323 A1 EP0647323 A1 EP 0647323A1 EP 93913193 A EP93913193 A EP 93913193A EP 93913193 A EP93913193 A EP 93913193A EP 0647323 A1 EP0647323 A1 EP 0647323A1
Authority
EP
European Patent Office
Prior art keywords
layers
magnetic
magnetic field
openings
electrodes
Prior art date
Legal status (The legal status 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 status listed.)
Withdrawn
Application number
EP93913193A
Other languages
German (de)
French (fr)
Inventor
Patrick Thomson-Csf Scpi Etienne
Alain Thomson-Csf Scpi Schuhl
Alain Thomson-Csf Scpi Friederich
Régis Thomson-CSF SCPI CABANEL
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Thales SA
Original Assignee
Thomson CSF SA
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 Thomson CSF SA filed Critical Thomson CSF SA
Publication of EP0647323A1 publication Critical patent/EP0647323A1/en
Withdrawn legal-status Critical Current

Links

Classifications

    • 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
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R33/00—Arrangements or instruments for measuring magnetic variables
    • G01R33/02—Measuring direction or magnitude of magnetic fields or magnetic flux
    • G01R33/06—Measuring direction or magnitude of magnetic fields or magnetic flux using galvano-magnetic devices
    • G01R33/09—Magnetoresistive devices
    • G01R33/093—Magnetoresistive devices using multilayer structures, e.g. giant magnetoresistance sensors
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
    • G11B5/127—Structure or manufacture of heads, e.g. inductive
    • G11B5/33—Structure or manufacture of flux-sensitive heads, i.e. for reproduction only; Combination of such heads with means for recording or erasing only
    • G11B5/39—Structure or manufacture of flux-sensitive heads, i.e. for reproduction only; Combination of such heads with means for recording or erasing only using magneto-resistive devices or effects
    • G11B5/3903—Structure or manufacture of flux-sensitive heads, i.e. for reproduction only; Combination of such heads with means for recording or erasing only using magneto-resistive devices or effects using magnetic thin film layers or their effects, the films being part of integrated structures

Definitions

  • the invention relates to a magnetic field detector and in particular a magnetic field detector with a magnetoresistive effect, namely a detector using the variation in resistivity of at least part of the detector as a function of a variation in magnetic field to which this subject is subjected. sensor part.
  • Sensors using the magnetoresistive effect are implemented in various magnetic recording reading systems. These sensors are made of a ferromagnetic alloy with high magnetoresistance which is placed in the
  • the alloys with strong magnetoresistance currently used are generally ferromagnetic alloys based on nickel, such as alloys of the type
  • the sensitive element of the sensor consists of a magnetic metallic multilayer
  • the object of the invention is to obtain a magnetoresistive type sensor sensitive to very weak magnetic fields.
  • the invention therefore relates to a magnetic field detector, characterized in that it comprises at least an alternation of layers of magnetic material and of layers of non-magnetic material, one or more openings passing through the alternation of layers, at least two electrodes placed on the sides of the alternating layers, facing one another with respect to the alternating layers so that at least one electrical path can exist between the two electrodes.
  • FIG. 7 an alternative embodiment in which the openings are filled with a non-magnetic or magnetic material in order to modify the coupling properties between the magnetic layers.
  • the invention makes it possible to produce a sensor for weak magnetic fields with magnetoresistive effect and with additional lateral coupling by using for the sensor a material based on multilayers.
  • the material shown in FIG. 1a is a multilayer made up of alternating layers of magnetic materials 1, l ', 1 "and non-magnetic 2, 2', 2".
  • the material is etched so as to obtain sides which then allow additional lateral coupling between the different magnetic layers of the multilayer (FIG. 1b).
  • the invention consists in etching the magnetoresistive element of the sensor, with patterns creating discontinuities in the structure. These discontinuities can have the double action, on the one hand of modifying the process of displacement of the walls of the magnetic domains, and on the other hand of introducing an additional coupling in the case where the film composing the sensor is based on multilayer material .
  • the two effects result in a modification of the field for which the magnetoresistance of the layer is maximum. This can then improve the magnetic field sensitivity of the magnetoresistive sensors.
  • Figure 2 shows an example of an etched pattern to increase the magnetoresistance at low field.
  • the walls of the magnetic domains are blocked by the etching patterns.
  • the grains delimited by these walls form magnetic monodomains. This collection of large magnetic moments is known for its high susceptibility in weak fields, in other words the system reacts to weaker fields.
  • FIG. 3 represents a perspective view of the sensor according to the invention making it possible to locate the elements of the sensor with respect to each other.
  • the openings are substantially perpendicular to the planes of layers 1 to 2 '.
  • electrodes 3 and 4 On the sides 6 and 7 of the layers 1 to 2 ′ are located electrodes 3 and 4 making it possible to connect an apparatus (not shown) for measuring the resistance of the layers 1 to 2 ′ according to the plane of these layers.
  • this magnetic field must have a significant value component located parallel to the planes of the layers.
  • the openings such as 5 may have different shapes so as to produce in the layers openings of different shapes.
  • the strip-shaped openings join the two electrodes 3 and 4. However, they could stop before the sides 6 and 7 which carry the electrodes.
  • the coupling force depends on the width of the bands and the thickness of the magnetic layers: for example, considering bands of 5 ⁇ m wide, with individual layers of iron of 2 nm thick, separated by non-magnetic layers of the same thickness, the lateral coupling between the layers is of the order of a hundred Gauss. With such a device, the layers are in the absence of magnetic field in an anti-parallel alignment. It takes a field of 100 Oe to place them in a parallel alignment and thus obtain the maximum magnetoresistance.
  • the strength of the coupling is directly related to the length of the edges of the discontinuities, relative to the surface of the sample.
  • it is the perimeter of the holes which determines the strength of this coupling.
  • the principle of the invention applies on the one hand to multilayers having in the absence of etching, a ferromagnetic type coupling between the magnetic layers, and on the other hand when the magnetic layers are not coupled together, as this is the case in Fe / Ag, Co / Ag systems.
  • the parameters of the engraved patterns will be calculated so that the additional anti-ferromagnetic coupling just cancels the ferromagnetic coupling so that the result of the two is a weak coupling of anti-ferromagnetic type.
  • the coupling could be as weak as desired.
  • the essential interest of the present invention comes from the great maneuverability of the type of coupling considered. Indeed, it is possible to decrease or increase the strength of the coupling simply by varying the shape of the etching patterns, the length of the flanks, or the spacing between the successive magnetic layers of the multilayer material. As in addition to the above-mentioned couplings, there is a direct coupling between the pieces of film located on either side of an etching pattern ( Figure 5) acting up to distances of the order of a few microns, it is possible to adjust the coupling by varying the width d of the openings.
  • the shape of the cutting edges can be optimized to increase the interactions between the different parts of the material separated by the openings. It is therefore important to define angles less than 90 degrees in order to allow the field lines to close.
  • polygonal patterns having angles at substantially 60 degrees create a leakage field on the current transport lines.
  • the strength of the additional lateral coupling by filling the etching holes with a material 9 whose magnetic permeability is different from that of air (FIG. 7).
  • the material can be non-magnetic but it can also be magnetic depending on whether one wishes to strengthen or decrease the coupling.

Landscapes

  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Chemical & Material Sciences (AREA)
  • Nanotechnology (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • General Physics & Mathematics (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Manufacturing & Machinery (AREA)
  • Measuring Magnetic Variables (AREA)

Abstract

A sensor comprising alternate layers of a magnetic material (1, 1', 1') and a non-magnetic material (2, 2', 2'). One or more openings (5) extend through said layers. Two electrodes (3, 4) on opposite sides of the layered stack enable measurement of the resistivity therebetween. Said openings (5) make the sensor more sensitive in weak fields and may have various shapes. Said sensor may be used in magnetic reading heads.

Description

DETECTEUR DE CHAMP MAGNETIQUE MAGNETIC FIELD DETECTOR
L'invention concerne un détecteur de champ magnétique et notamment un détecteur de champ magnétique à effet magnétorésistif, à savoir un détecteur utilisant la variation de résistivité d'une partie au moins du détecteur en fonction d'une variation de champ magnétique auquel est soumise cette partie de capteur.The invention relates to a magnetic field detector and in particular a magnetic field detector with a magnetoresistive effect, namely a detector using the variation in resistivity of at least part of the detector as a function of a variation in magnetic field to which this subject is subjected. sensor part.
Des capteurs utilisant l'effet magnétorésistif sont mis en oeuvre dans divers systèmes de lecture d'enregistrement magnétique . Ces capteurs sont réalisés en un alliage ferromagnétique à forte magnétorésistance qui est placé dans leSensors using the magnetoresistive effect are implemented in various magnetic recording reading systems. These sensors are made of a ferromagnetic alloy with high magnetoresistance which is placed in the
10 circuit magnétique d'une tête de lecture . Dans ce cas , on détecte les variations de la résistance électrique du capteur lors du passage de la bande . Les alliages à forte magnétorésistance actuellement utilisés sont en général des alliages ferromagnétiques à base de nickel, tels que les alliages de type10 magnetic circuit of a read head. In this case, variations in the electrical resistance of the sensor are detected during the passage of the strip. The alloys with strong magnetoresistance currently used are generally ferromagnetic alloys based on nickel, such as alloys of the type
15 NiFe ou NiCo, pour lesquels la magnétorésistance à température ambiante correspond à une variation de résistance de quelques pour cent.15 NiFe or NiCo, for which the magnetoresistance at room temperature corresponds to a variation in resistance of a few percent.
Dans des capteurs plus récents, l'élément sensible du capteur est constitué par une multicouche métallique magnétiqueIn more recent sensors, the sensitive element of the sensor consists of a magnetic metallic multilayer
20 monocristalline formée d'un empilement de couches d'un matériau magnétique, la multicouche étant réalisée de telle sorte que les couches en matériau magnétique présentent une situation de type anti- ferromagnétique en l'absence de champ extérieur et que la transition entre l'état d'arrangement anti -parallèle et l'état20 monocrystalline formed of a stack of layers of magnetic material, the multilayer being produced so that the layers of magnetic material present an anti-ferromagnetic type situation in the absence of an external field and that the transition between the anti-parallel arrangement state and state
~ ** d'arrangement parallèle se réalise sur un intervalle de champ magnétique faible .~ ** of parallel arrangement is carried out on a weak magnetic field interval.
Ainsi, en utilisant certains types de matériaux magnétiques et non magnétiques , associés selon une structure spécifique, on a pu observer une magnétorésistance géante seThus, by using certain types of magnetic and non-magnetic materials, associated according to a specific structure, we could observe a giant magnetoresistance
30 produisant dans un domaine de champ restreint, ce qui permet donc son utilisation comme élément sensible d'un capteur à effet magnétorésistif . Cette forte magnétorésistance observée notamment dans le cadre des multicouches métalliques magnétiques telles que Fe/Cr est due à la transition sous champ magnétique entre les deux états d'aimantation du système, à savoir l'état où l'alternance des aimantations des couches magnétiques est anti-parallèle et l'état où toutes ces aimantations sont parallèles .30 producing in a restricted field, which therefore allows its use as a sensitive element of a magnetoresistive effect sensor. This strong magnetoresistance observed in particular within the framework of magnetic metallic multilayers such as Fe / Cr is due to the transition under magnetic field between the two states of magnetization of the system, namely the state where the alternation of the magnetizations of the magnetic layers is anti-parallel and the state where all these magnetizations are parallel.
Le principal inconvénient de ces capteurs reste la haute valeur du champ magnétique H nécessaire pour faireThe main disadvantage of these sensors remains the high value of the magnetic field H necessary to make
S transiter les aimantations de l'état anti- parallèle à l'état parallèle . En effet, la sensibilité du capteur se mesure par la pente de variation de la magnétorésistance en fonction du champ magnétique . La valeur élevée de H relativise l'avantage que constitue la magnétorésistance géante de ces matériaux .Transition the magnetizations from the anti-parallel state to the parallel state. Indeed, the sensitivity of the sensor is measured by the slope of variation of the magnetoresistance as a function of the magnetic field. The high value of H puts the advantage of the giant magnetoresistance of these materials into perspective.
L'objet de l'invention est d'obtenir un capteur de type magnétorésistif sensible à de très faibles champs magnétiques . L'invention concerne donc un détecteur de champ magnétique, caractérisé en ce qu'il comporte au moins une alternance de couches en matériau magnétique et de couches en matériau non magnétique , une ou plusieurs ouvertures traversant l'alternance de couches, au moins deux électrodes placées sur des flancs de l'alternance de couches, en vis-à-vis l'une de l'autre par rapport à l'alternance de couches de telle façon qu'au moins un chemin électrique puisse exister entre les deux électrodes .The object of the invention is to obtain a magnetoresistive type sensor sensitive to very weak magnetic fields. The invention therefore relates to a magnetic field detector, characterized in that it comprises at least an alternation of layers of magnetic material and of layers of non-magnetic material, one or more openings passing through the alternation of layers, at least two electrodes placed on the sides of the alternating layers, facing one another with respect to the alternating layers so that at least one electrical path can exist between the two electrodes.
Les différents objets et caractéristiques de l'invention apparaîtront plus clairement dans la description qui va suivre et dans les figures annexées qui représentent :The various objects and characteristics of the invention will appear more clearly in the description which follows and in the appended figures which represent:
- les figures la, lb et 2 , un exemple de réalisation simplifié du dispositif selon l'invention ;- Figures la, lb and 2, a simplified embodiment of the device according to the invention;
- la figure 3 , une vue en perspective du dispositif de l'invention ;- Figure 3, a perspective view of the device of the invention;
- la figure 4, un dispositif dans lequel les ouvertures sont des rainures ;- Figure 4, a device in which the openings are grooves;
- la figure 5 , une figure explicative concernant les ouvertures : - la figure 6, une variante de réalisation dans laquelle les ouvertures sont de forme polygonale ;- Figure 5, an explanatory figure concerning the openings: - Figure 6, an alternative embodiment in which the openings are of polygonal shape;
- la figure 7, une variante de réalisation dans laquelle les ouvertures sont remplies d'un matériau non magnétique ou magnétique afin de modifier les propriétés de couplage entre les couches magnétiques .- Figure 7, an alternative embodiment in which the openings are filled with a non-magnetic or magnetic material in order to modify the coupling properties between the magnetic layers.
L'invention permet de réaliser un capteur de champs magnétiques faibles à effet magnétorésistif et à couplage latéral supplémentaire en utilisant pour le capteur un matériau à base de multicouches .The invention makes it possible to produce a sensor for weak magnetic fields with magnetoresistive effect and with additional lateral coupling by using for the sensor a material based on multilayers.
Le matériau représenté en figure la est une multicouche constituée de couches alternées de matériaux magnétiques 1, l' , 1" et non magnétiques 2, 2', 2" . Dans l'application considérée, le matériau est gravé de manière à obtenir des flancs qui permettent alors un couplage latéral supplémentaire entre les différentes couches magnétiques de la multicouche (figure lb) .The material shown in FIG. 1a is a multilayer made up of alternating layers of magnetic materials 1, l ', 1 "and non-magnetic 2, 2', 2". In the application considered, the material is etched so as to obtain sides which then allow additional lateral coupling between the different magnetic layers of the multilayer (FIG. 1b).
L'invention consiste à graver l'élément magnétorésistif du capteur, avec des motifs créant des discontinuités dans la structure. Ces discontinuités peuvent avoir la double action, d'une part de modifier le processus de déplacement des parois des domaines magnétiques, et d'autre part d'introduire un couplage supplémentaire dans le cas où le film composant le capteur est à base de matériau multicouches . Les deux effets ont pour conséquence une modification du champ pour lequel la magnétorésistance de la couche est maximale . Cela peut améliorer alors la sensibilité en champ magnétique des capteurs magnétorésistif s .The invention consists in etching the magnetoresistive element of the sensor, with patterns creating discontinuities in the structure. These discontinuities can have the double action, on the one hand of modifying the process of displacement of the walls of the magnetic domains, and on the other hand of introducing an additional coupling in the case where the film composing the sensor is based on multilayer material . The two effects result in a modification of the field for which the magnetoresistance of the layer is maximum. This can then improve the magnetic field sensitivity of the magnetoresistive sensors.
La figure 2 montre un exemple de motif gravé permettant d'augmenter la magnétorésistance à faible champ . Dans cet exemple les parois des domaines magnétiques sont bloquées par les motifs de gravure . Les grains délimités par ces parois forment des monodomaines magnétiques . Cette collection de gros moments magnétiques est connue pour sa forte susceptibilité en champs faibles , en d'autres termes le système réagit à des champs plus faibles .Figure 2 shows an example of an etched pattern to increase the magnetoresistance at low field. In this example, the walls of the magnetic domains are blocked by the etching patterns. The grains delimited by these walls form magnetic monodomains. This collection of large magnetic moments is known for its high susceptibility in weak fields, in other words the system reacts to weaker fields.
La figure 3 représente une vue en perspective du capteur selon l'invention permettant de situer les éléments du capteur les uns par rapport aux autres .FIG. 3 represents a perspective view of the sensor according to the invention making it possible to locate the elements of the sensor with respect to each other.
On trouve, dans ce capteur, l'empilement de couches 1 , 2, l' , 2' , . . . et les ouvertures tels que 5 traversant ces couches . De façon préférentielle, les ouvertures sont sensiblement perpendiculaires aux plans des couches 1 à 2' . Sur les flancs 6 et 7 des couches 1 à 2' sont situées des électrodes 3 et 4 permettant de connecter un appareil (non représenté) pour mesurer la résistance des couches 1 à 2' selon le plan de ces couches .In this sensor, we find the stack of layers 1, 2, l ', 2',. . . and openings such as 5 passing through these layers. Preferably, the openings are substantially perpendicular to the planes of layers 1 to 2 '. On the sides 6 and 7 of the layers 1 to 2 ′ are located electrodes 3 and 4 making it possible to connect an apparatus (not shown) for measuring the resistance of the layers 1 to 2 ′ according to the plane of these layers.
Les couches 1 , l' étant en matériau magnétique et les couches 2 , 2' étant en matériau non magnétique il existe un couplage anti- ferromagnétique entre les couches 1 et l' . En l'absence d'application de champ magnétique la résistance mesurée entre les électrodes est minimale .The layers 1, the being in magnetic material and the layers 2, 2 'being in non-magnetic material there is an anti-ferromagnetic coupling between the layers 1 and the. In the absence of magnetic field application, the resistance measured between the electrodes is minimal.
Sous l'effet d'un champ magnétique extérieur, le champ magnétique dans les différentes couches en matériau magnétique s'aligne selon la direction de ce champ magnétique et la résistance entre les électrodes augmente . De préférence, il faut que ce champ magnétique possède une composante de valeur importante située parallèlement aux plans des couches .Under the effect of an external magnetic field, the magnetic field in the different layers of magnetic material is aligned in the direction of this magnetic field and the resistance between the electrodes increases. Preferably, this magnetic field must have a significant value component located parallel to the planes of the layers.
Les ouvertures telles que 5 peuvent avoir des formes différentes de façon à réaliser dans les couches des ouvertures de formes différentes .The openings such as 5 may have different shapes so as to produce in the layers openings of different shapes.
C'est ainsi que les ouvertures peuvent être réalisées sous forme de bandes comme cela est représenté en figure 4.This is how the openings can be made in the form of strips as shown in FIG. 4.
Sur cette figure, les ouvertures sous forme de bandes joignent les deux électrodes 3 et 4. Cependant, elles pourraient s'arrêter avant les flancs 6 et 7 qui portent les électrodes .In this figure, the strip-shaped openings join the two electrodes 3 and 4. However, they could stop before the sides 6 and 7 which carry the electrodes.
Dans le cas de ces bandes , la force de couplage dépend de la largeur des bandes et de l'épaisseur des couches magnétiques : par exemple, en considérant des bandes de 5 μm de large, avec des couches individuelles de fer de 2nm d'épaisseur, séparées par des couches non magnétiques de même épaisseur, le couplage latéral entre les couches est de l'ordre de la centaine de Gauss . Avec un tel dispositif , les couches sont en l'absence de champ magnétique dans un alignement anti- parallèle . Il faut un champ de 100 Oe pour les placer dans un alignement parallèle et donc obtenir la magnétorésistance maximale .In the case of these bands, the coupling force depends on the width of the bands and the thickness of the magnetic layers: for example, considering bands of 5 μm wide, with individual layers of iron of 2 nm thick, separated by non-magnetic layers of the same thickness, the lateral coupling between the layers is of the order of a hundred Gauss. With such a device, the layers are in the absence of magnetic field in an anti-parallel alignment. It takes a field of 100 Oe to place them in a parallel alignment and thus obtain the maximum magnetoresistance.
Il est important de noter que la force du couplage est directement reliée à la longueur des bords des discontinuités, rapportée à la surface de l'échantillon . Ainsi, pour un motif de gravure du type de celui de la figure 1 , c'est le périmètre des trous qui détermine la force de ce couplage .It is important to note that the strength of the coupling is directly related to the length of the edges of the discontinuities, relative to the surface of the sample. Thus, for an etching pattern of the type of that of FIG. 1, it is the perimeter of the holes which determines the strength of this coupling.
Le principe de l'invention s'applique d'une part aux multicouches présentant en l'absence de gravure, un couplage de type ferromagnétique entre les couches magnétiques, et d'autre part lorsque les couches magnétiques ne sont pas couplées entre elles, comme c'est le cas dans les systèmes Fe/Ag, Co/Ag . Dans le premier cas, les paramètres des motifs gravés seront calculés pour que le couplage anti-ferromagnétique supplémentaire annule juste le couplage ferromagnétique afin que la résultante des deux soit un faible couplage de type anti-ferromagnétique . Dans le second cas, le couplage pourra être aussi faible que voulu . Il est à noter toutefois , que dans les deux cas , le couplage résultant de type anti-ferromagnétiqτιe doit être supérieur à toutes les autres énergies magnétiques mises en jeu dans les couches minces ; l'anisotropie , et la coercivité, etc . . . Dans les meilleurs systèmes cette valeur limite peut être de l'ordre duThe principle of the invention applies on the one hand to multilayers having in the absence of etching, a ferromagnetic type coupling between the magnetic layers, and on the other hand when the magnetic layers are not coupled together, as this is the case in Fe / Ag, Co / Ag systems. In the first case, the parameters of the engraved patterns will be calculated so that the additional anti-ferromagnetic coupling just cancels the ferromagnetic coupling so that the result of the two is a weak coupling of anti-ferromagnetic type. In the second case, the coupling could be as weak as desired. It should be noted, however, that in both cases, the resulting coupling of anti-ferromagnetic type must be greater than all the other magnetic energies involved in the thin layers; anisotropy, and coercivity, etc. . . In the best systems this limit value can be of the order of
Gauss .Gauss.
L'intérêt essentiel de la présente invention provient de la grande maniabilité du type de couplage considéré . En effet, il est possible de diminuer ou d'augmenter la force du couplage simplement en faisant varier la forme des motifs de gravure , la longueur des flancs , ou l'espacement entre les couches magnétiques successives du matériau multicouche . Comme en plus des couplages sus-cités, il existe un couplage direct entre les morceaux de film situés de part et d'autre d'un motif de gravure (figure 5) agissant jusqu'à des distances de l'ordre de quelques microns, il est possible d'ajuster le couplage en faisant varier la largeur d des ouvertures .The essential interest of the present invention comes from the great maneuverability of the type of coupling considered. Indeed, it is possible to decrease or increase the strength of the coupling simply by varying the shape of the etching patterns, the length of the flanks, or the spacing between the successive magnetic layers of the multilayer material. As in addition to the above-mentioned couplings, there is a direct coupling between the pieces of film located on either side of an etching pattern (Figure 5) acting up to distances of the order of a few microns, it is possible to adjust the coupling by varying the width d of the openings.
La forme des flancs de découpe peut être optimisée pour augmenter les interactions entre les différentes parties du matériau séparées pas les ouvertures . Il est alors important de définir des angles inférieurs à 90 degrés afin de permettre aux lignes de champs de se refermer . Dans l'exemple de réalisation de cette extension de l'invention, présentée sur la figure G, des motifs poligonaux présentant des angles à sensiblement 60 degrés créent un champ de fuite sur les lignes de transport de courant .The shape of the cutting edges can be optimized to increase the interactions between the different parts of the material separated by the openings. It is therefore important to define angles less than 90 degrees in order to allow the field lines to close. In the exemplary embodiment of this extension of the invention, presented in FIG. G, polygonal patterns having angles at substantially 60 degrees create a leakage field on the current transport lines.
Dans un autre prolongement de l'invention, il est possible de modifier la force du couplage supplémentaire latéral, en remplissant les trous de gravure par un matériau 9 dont la perméabilité magnétique est différente de celle de l'air (figure 7) . Le matériau peut être non magnétique mais il peut également être magnétique suivant que l'on désire renforcer ou diminuer le couplage . In another extension of the invention, it is possible to modify the strength of the additional lateral coupling, by filling the etching holes with a material 9 whose magnetic permeability is different from that of air (FIG. 7). The material can be non-magnetic but it can also be magnetic depending on whether one wishes to strengthen or decrease the coupling.

Claims

REVENDICATIONS
1. Détecteur de champ magnétique, caractérisé en ce qu'il comporte au moins une alternance de couches en matériau magnétique (1, l', 1") et de couches en matériau non magnétique (2, 2', 2") , une ou plusieurs ouvertures (5) traversant l'alternance de couches, au moins deux électrodes (3, 4) placées sur des flancs de l'alternance de couches, de telle façon qu'au moins un chemin électrique puisse exister entre les deux électrodes .1. Magnetic field detector, characterized in that it comprises at least an alternation of layers of magnetic material (1, l ', 1 ") and of layers of non-magnetic material (2, 2', 2"), a or several openings (5) passing through the alternating layers, at least two electrodes (3, 4) placed on the sides of the alternating layers, so that at least one electrical path can exist between the two electrodes.
2. Détecteur selon la revendication 1, caractérisé en ce que les électrodes (3, 4) sont placées sur deux flancs opposés de l'alternance de couches en vis-à-vis l'une de l'autre par rapport à l'alternance de couches .2. Detector according to claim 1, characterized in that the electrodes (3, 4) are placed on two opposite sides of the alternation of layers opposite one another with respect to the alternation of layers.
3. Détecteur de champ magnétique selon la revendication 1, caractérisé en ce que les ouvertures (5) ont leur section parallèle au plan des couches, de forme circulaire ou poly onale .3. Magnetic field detector according to claim 1, characterized in that the openings (5) have their section parallel to the plane of the layers, circular or poly onal.
4. Détecteur de champ magnétique selon la revendication 2, caractérisé en ce que les ouvertures ont leur section de forme sensiblement carrée .4. Magnetic field detector according to claim 2, characterized in that the openings have their section of substantially square shape.
5. Détecteur de champ magnétique selon la revendication 1, caractérisé en ce que les ouvertures sont des découpes allongées non parallèles au plan des électrodes .5. Magnetic field detector according to claim 1, characterized in that the openings are elongated cutouts not parallel to the plane of the electrodes.
6. Détecteur de champ magnétique selon la revendication 4, caractérisé en ce que les ouvertures joignent sensiblement les deux électrodes .6. Magnetic field detector according to claim 4, characterized in that the openings substantially join the two electrodes.
7. Détecteur de champ magnétique selon la revendication 4, caractérisé en ce que les ouvertures sont perpendiculaires au plan des électrodes .7. Magnetic field detector according to claim 4, characterized in that the openings are perpendicular to the plane of the electrodes.
8. Détecteur de champ magnétique selon la revendication 1, caractérisé en ce que chaque ouverture comporte un matériau (9) et dont la perméabilité magnétique est supérieure à celle de l'air. 8. Magnetic field detector according to claim 1, characterized in that each opening comprises a material (9) and whose magnetic permeability is greater than that of air.
9. Détecteur selon la revendication 8, caractérisé en ce que le matériau (9) de chaque ouverture est un matériau non magnétique .9. Detector according to claim 8, characterized in that the material (9) of each opening is a non-magnetic material.
10. Détecteur selon la revendication 8, caractérisé en ce que le matériau (9) de chaque ouverture est un matériau magnétique . 10. Detector according to claim 8, characterized in that the material (9) of each opening is a magnetic material.
EP93913193A 1992-06-26 1993-06-25 Magnetic field sensor Withdrawn EP0647323A1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
FR9207881 1992-06-26
FR9207881A FR2693021B1 (en) 1992-06-26 1992-06-26 Magnetic field detector.
PCT/FR1993/000640 WO1994000774A1 (en) 1992-06-26 1993-06-25 Magnetic field sensor

Publications (1)

Publication Number Publication Date
EP0647323A1 true EP0647323A1 (en) 1995-04-12

Family

ID=9431240

Family Applications (1)

Application Number Title Priority Date Filing Date
EP93913193A Withdrawn EP0647323A1 (en) 1992-06-26 1993-06-25 Magnetic field sensor

Country Status (3)

Country Link
EP (1) EP0647323A1 (en)
FR (1) FR2693021B1 (en)
WO (1) WO1994000774A1 (en)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5452163A (en) * 1993-12-23 1995-09-19 International Business Machines Corporation Multilayer magnetoresistive sensor
DE19949714A1 (en) * 1999-10-15 2001-04-26 Bosch Gmbh Robert Magnetically sensitive component used as a sensor element operating according to a spin-valve principle in vehicles comprises two magneto-resistive layer systems with a reference layer, an intermediate layer and a detection layer

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS62183016A (en) * 1985-06-28 1987-08-11 Nec Kansai Ltd Magneto-resistance effect head
FR2648942B1 (en) * 1989-06-27 1995-08-11 Thomson Csf SENSOR WITH MAGNETORESISTIVE EFFECT
DE69106334T2 (en) * 1990-12-10 1995-05-04 Hitachi Ltd Multi-view film with magnetoresistive effect and magnetoresistive element.
JPH1073517A (en) * 1996-08-30 1998-03-17 Toyota Motor Corp Testing apparatus for motive power source of hybrid vehicle

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO9400774A1 *

Also Published As

Publication number Publication date
WO1994000774A1 (en) 1994-01-06
FR2693021B1 (en) 1994-08-26
FR2693021A1 (en) 1993-12-31

Similar Documents

Publication Publication Date Title
EP2038671B1 (en) Method and system for adjusting the sensitivity of a magnetoresistive sensor
EP1055259B1 (en) Magnetoresistor with tunnel effect and magnetic sensor using same
EP0724302B1 (en) Magnetic sensor with a giant magnetoresistance, and its method of fabrication
US20030070497A1 (en) Rotation angle sensor capable of accurately detecting rotation angle
EP0577469B1 (en) Magnetoresistive transducer
FR2876800A1 (en) METHOD AND DEVICE FOR MEASURING A MAGNETIC FIELD USING A MAGNETORESITIVE SENSOR
EP0721670B1 (en) Current sensor comprising a magnetoresistive strip and method of production
FR2539542A1 (en) MAGNETIC HEAD OF READING
EP0853766A1 (en) Magnetic field sensor with magnetoresistor bridge
FR2911690A1 (en) MAGNETIC AMPLIFICATION DEVICE COMPRISING A MAGNETIC SENSOR WITH LONGITUDINAL SENSITIVITY
EP0642181B1 (en) Magnetoresistive device and sensor with a geometric repetitive pattern
EP3009853B1 (en) Magnetic field sensor for detecting at least two magnetic field components
EP0660128B1 (en) Thin film magnetic field detector
FR2709549A1 (en) Magnetic flux guide with tabs and magnetoresistive sensor including this guide.
KR100319423B1 (en) Spin-valve type magnetoresistive thin film element and its manufacturing method
FR2787197A1 (en) MAGNETIC FIELD SENSOR WITH GIANT MAGNETORESISTANCE
EP0647323A1 (en) Magnetic field sensor
WO2015166159A1 (en) Permanent magnet comprising a stack of ferromagnetic and antiferromagnetic layers
FR2828001A1 (en) Magnetic random access memory magnetic switching command having electrode planes/ferromagnetic layer thickness lower than first and electrode thickness allowing magnetic coupling.
FR2800914A1 (en) MAGNETORESISTANT LAYER SYSTEM
FR2677811A1 (en) Device including a super-network of layers having giant magnetoresistance properties which are produced on a semiconducting substrate
EP3070462B1 (en) Device and method for detecting a magnetic inhomogeneity in a ferromagnetic material
FR2772965A1 (en) Magnetic sensor for use in magnetic read head
Oh et al. Etching effect on exchange anisotropy in NiFe/Cu/NiFe/IrMn spin-valve structure for an array of PHR sensor element
FR2772966A1 (en) High sensitivity magneto-resistant read head

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

17P Request for examination filed

Effective date: 19941209

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): DE GB

17Q First examination report despatched

Effective date: 19950407

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN

18D Application deemed to be withdrawn

Effective date: 19960818