EP1046046A1 - Magnetoresistive sensor element, especially angular sensor element - Google Patents

Magnetoresistive sensor element, especially angular sensor element

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Publication number
EP1046046A1
EP1046046A1 EP99924763A EP99924763A EP1046046A1 EP 1046046 A1 EP1046046 A1 EP 1046046A1 EP 99924763 A EP99924763 A EP 99924763A EP 99924763 A EP99924763 A EP 99924763A EP 1046046 A1 EP1046046 A1 EP 1046046A1
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EP
European Patent Office
Prior art keywords
layer
sensor element
element according
magnetization
magnetic
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.)
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EP99924763A
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German (de)
French (fr)
Inventor
Klaus Marx
Franz Jost
Martin Freitag
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Robert Bosch GmbH
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Robert Bosch GmbH
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Publication of EP1046046A1 publication Critical patent/EP1046046A1/en
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Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
    • G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
    • G01D5/12—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means
    • G01D5/14—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage
    • G01D5/142—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage using Hall-effect devices
    • G01D5/145—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage using Hall-effect devices influenced by the relative movement between the Hall device and magnetic fields
    • 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
    • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B7/00—Measuring arrangements characterised by the use of electric or magnetic techniques
    • G01B7/30—Measuring arrangements characterised by the use of electric or magnetic techniques for measuring angles or tapers; for testing the alignment of axes
    • 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
    • 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
    • H01F10/3268—Exchange coupling of magnetic film pairs via a very thin non-magnetic spacer, e.g. by exchange with conduction electrons of the spacer the exchange coupling being asymmetric, e.g. by use of additional pinning, by using antiferromagnetic or ferromagnetic coupling interface, i.e. so-called spin-valve [SV] structure, e.g. NiFe/Cu/NiFe/FeMn
    • H01F10/3281—Exchange coupling of magnetic film pairs via a very thin non-magnetic spacer, e.g. by exchange with conduction electrons of the spacer the exchange coupling being asymmetric, e.g. by use of additional pinning, by using antiferromagnetic or ferromagnetic coupling interface, i.e. so-called spin-valve [SV] structure, e.g. NiFe/Cu/NiFe/FeMn only by use of asymmetry of the magnetic film pair itself, i.e. so-called pseudospin valve [PSV] structure, e.g. NiFe/Cu/Co

Definitions

  • Magnetoresistive sensor element in particular angle sensor element
  • the present invention relates to a magnetoresistive sensor element, in particular an angle sensor element, according to the preamble of patent claim 1.
  • Sensors in particular angle sensors, which work on the basis of the magnetoresistive effect are known.
  • the electrical resistance of sensor elements is measured as a function of the direction of an external magnetic field.
  • GMR sensor elements giant magneto resistance
  • self-stabilizing magnetic layers van den Berg et al., GMR angle detector with an artificial antiferromagnetic subsystem , Journal of Magnetism and Magnetic Materials 165 (1997) 524-528.
  • a first thin, so-called reference layer is generated by the fact that between two oppositely magnetized layers (for example made of Co) an antiferromagnetic coupling layer (for example made of Cu or Ru) is introduced.
  • the magnetic stability of the reference layer is increased by an order of magnitude compared to individual Co layers due to this multilayer structure.
  • the direction of magnetization of the reference layer does not (ideally) depend on the direction of the external (to be measured) magnetic field.
  • the reference layer is covered with a thin non-magnetic layer, on which in turn a thin soft magnetic layer, the so-called detection layer, is formed.
  • Angular errors are essentially caused by two factors.
  • the magnetic reference is influenced by the magnetic field to be measured and does not remain rigid in the excellent direction
  • the magnetization direction follows the Detection layer not free of errors or delays in the direction of the external magnetic field.
  • the object of the invention is therefore to create a magnetoresistive sensor element or sensor with which occurring angle errors can be avoided or at least reduced.
  • a sensor element is now created in which the direction of magnetization of the detection layer can follow an external magnetic field, in particular even with an external magnetic field that is small in terms of magnitude, much more easily and more accurately or more delay-free than was possible with conventional sensor elements.
  • the " improvement in the accuracy of the sensor element that can be achieved in this way can be achieved with little technical effort (for example structuring of the detection layer by known chemical methods).
  • the segments are at least partially circular or elliptical. With such a shape, a particularly delay-free or precise alignment of the direction of magnetization of the detection layer with respect to an external magnetic field is obtained.
  • the sensor element expediently has an elongated or elongated shape. This design ensures that the reference magnetization is largely independent of the external magnetic field.
  • the elongated shape or the anisotropy of the sensor element (its length should be significantly greater than its width) has a particularly favorable effect on the self-stabilization of a reference layer designed as an artificial antiferromagnet.
  • the first layer is expediently a hard magnetic layer.
  • Such layers are inexpensive to implement and ensure good magnetic stability of the reference layer.
  • the third layer is expediently designed as a soft magnetic layer.
  • Such layers can be implemented in a variety of different forms in a simple and inexpensive manner.
  • Ni-Fe alloys may be mentioned as a preferred example of soft magnetic materials.
  • the first layer consists of a layer arrangement with a self-stabilizing coupling (artificial antiferromagnet).
  • Such layers have a particularly high magnetic stability, furthermore an elongated shape of the Sensor element on the magnetic stability of such layer arrangements particularly favorable.
  • the first layer has an artificially pinned or biased magnetization.
  • magnetization can be achieved, for example, by means of a current-carrying conductor which is in operative connection with the first layer in order to stabilize its direction of magnetization.
  • the first and third layers are made using GMR materials.
  • Figure 1 is a schematic plan view of a preferred embodiment of the sensor element according to the invention.
  • Figure 2 shows the sensor element of Figure 1 schematically in a side view
  • the sensor element shown in FIG. 1 has a first, magnetic or magnetized layer 1, which represents a reference layer.
  • the internal structure of this first layer is not shown in detail. It is preferred that the first layer 1 is designed as an artificial antiferromagnet, ie between two thin magnetic layers with (in the basic state) antiparallel oriented magnetizations as antiferromagnetic coupling layer acting thin metallic intermediate layer.
  • an artificial antiferromagnet ie between two thin magnetic layers with (in the basic state) antiparallel oriented magnetizations as antiferromagnetic coupling layer acting thin metallic intermediate layer.
  • the magnetic framework necessary for the creation of a self-stabilizing artificial antiferromagnet reference is made to the article by van den Berg et. al. directed.
  • the direction of the reference magnetization created by the first layer 1 is shown in FIG. 1 and FIG. 2 by an arrow 5.
  • the direction of an external magnetic field to be measured is shown by the dashed arrow 6.
  • a thin, non-magnetic second layer 2 is applied to the first layer 1, on which in turn a magnetic third layer 3 (detection layer) is formed.
  • the layer system with the layers 1, 2, 3 is advantageously produced in the schematically illustrated elongated (or also a meandered) form, the third layer 3 also initially being unstructured, i.e. is formed according to layers 1, 2.
  • the third layer 3 is then removed, for example by means of chemical processes (e.g.
  • Etching process in the form of the illustrated ellipses 3a or in the form of circles selectively structured. Structuring of this type proves to be very favorable for the sensor function, since this means that the direction of magnetization can also follow relatively small external magnetic fields with relative amounts.
  • the (the direction 6 of the outer Magnetization corresponding to the magnetic field is represented by arrows 7 for the respective ellipses 3a.
  • the sensor elements according to the invention can be connected, for example, to bridge circuits in a manner known per se. With sensors that use such bridge circuits, angle measurements are possible in a particularly simple and reliable manner.

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • General Physics & Mathematics (AREA)
  • Chemical & Material Sciences (AREA)
  • Nanotechnology (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • Power Engineering (AREA)
  • Measuring Magnetic Variables (AREA)
  • Hall/Mr Elements (AREA)
  • Thin Magnetic Films (AREA)
  • Measurement Of Length, Angles, Or The Like Using Electric Or Magnetic Means (AREA)
  • Transmission And Conversion Of Sensor Element Output (AREA)
  • Magnetic Heads (AREA)

Abstract

The invention relates to a magnetoresistive sensor element, especially an angular sensor element, having a first magnetic layer (1) whose magnetization direction represents a direction reference, a second non magnetic layer (2) formed on the first layer (1) and a third magnetic layer (3) formed on the second layer, the magnetization direction of said third layer being influenced by an external magnetic field, wherein the third layer (3) is at least partially embodied as individual segments (3a).

Description

Maσnetoresistives Sensorelement, insbesondere WinkelsensorelementMagnetoresistive sensor element, in particular angle sensor element
Die vorliegende Erfindung betrifft ein magnetoresist ives Sensorelement, insbesondere ein Winkelsensorelement, nach dem Oberbegriff des Patentanspruchs 1.The present invention relates to a magnetoresistive sensor element, in particular an angle sensor element, according to the preamble of patent claim 1.
Sensoren, insbesondere WinkelSensoren, die auf der Grundlage des magnetoresistiven Effektes arbeiten, sind bekannt. Hierbei wird der elektrische Widerstand von Sensorelementen in Abhängigkeit von der Richtung eines äußeren Magnetfeldes gemessen. Es sind beispielsweise Systeme beschrieben worden, bei welchen sogenannte GMR- Sensorelemente (engl.: Giant-Magneto-Resistance) , insbesondere unter Verwendung von selbstabilisierenden magnetischen Schichten, eingesetzt werden (van den Berg et al . , GMR angle detector with an artificial antiferromagnetic Subsystem, Journal of Magnetism and Magnetic Materials 165 (1997) 524-528) . Hierbei wird eine erste dünne, sogenannte Referenzschicht dadurch erzeugt, daß zwischen zwei entgegengesetzt magnetisierten Lagen (beispielsweise aus Co) eine antiferromagnetische Kopplungsschicht (beispielsweise aus Cu oder Ru) eingebracht wird. Die magnetische Stabilität der Referenzschicht ist durch diesen Mehrschicht-Aufbau __ gegenüber einzelnen Co-Schichten um etwa eine Größenordnung erhöht. Die Magnetisierungsrichtung der Referenzschicht hängt (im Idealfall) nicht von der Richtung des äußeren (zu messenden) Magnetfeldes ab.Sensors, in particular angle sensors, which work on the basis of the magnetoresistive effect are known. The electrical resistance of sensor elements is measured as a function of the direction of an external magnetic field. For example, systems have been described in which so-called GMR sensor elements (giant magneto resistance) are used, in particular using self-stabilizing magnetic layers (van den Berg et al., GMR angle detector with an artificial antiferromagnetic subsystem , Journal of Magnetism and Magnetic Materials 165 (1997) 524-528). Here, a first thin, so-called reference layer is generated by the fact that between two oppositely magnetized layers (for example made of Co) an antiferromagnetic coupling layer (for example made of Cu or Ru) is introduced. The magnetic stability of the reference layer is increased by an order of magnitude compared to individual Co layers due to this multilayer structure. The direction of magnetization of the reference layer does not (ideally) depend on the direction of the external (to be measured) magnetic field.
Die Referenzschicht ist mit einer dünnen nicht-magnetischen Schicht abgedeckt , auf der wiederum eine dünne weichmagnetische Schicht, die sogenannte Detektionsschicht, ausgebildet ist. Die Detektionsschicht richtet ihre Magnetisierung (wiederum im Idealfall) , auch bei betragsmäßig kleinen Feldern, in Richtung eines äußeren Magnetfeldes aus. Aus der Theorie des GMR-Effektes ist bekannt, daß ein Sensorsignal einer Funktion R(α) = R0 + ΔR*sin(α) folgt , wobei R0 ein Offsetwiderstand, ΔR ein Signalhub des Sensors und der zu messende Winkel zwischen einer ausgezeichneten Sensorrichtung (insbesondere derThe reference layer is covered with a thin non-magnetic layer, on which in turn a thin soft magnetic layer, the so-called detection layer, is formed. The detection layer orients its magnetization (again, ideally), even in the case of small fields, towards an external magnetic field. It is known from the theory of the GMR effect that a sensor signal follows a function R (α) = R 0 + ΔR * sin (α), where R 0 is an offset resistance, ΔR is a signal swing of the sensor and the angle to be measured between an excellent one Sensor direction (especially the
Referenzrichtung) und der Richtung des äußeren Magnetfeldes ist.Reference direction) and the direction of the external magnetic field.
Als nachteilig bei derartigen Systemen erweist sich, daß es aufgrund verschiedener magnetischer Wechselwirkungen bzw. Effekte zu Ungenauigkeiten bzw. Fehlern bei der Winkelbestimmung kommen kann. Winkelfehler werden im wesentlichen durch zwei Faktoren verursacht. Zum einen wird die magnetische Referenz von dem zu messenden Magnetfeld beeinflußt und bleibt nicht starr in der ausgezeichneten Richtung, zum anderen folgt die Magnetisierungrichtung der Detektionsschicht nicht fehler- bzw. verzögerungsfrei der Richtung des äußeren Magnetfeldes .A disadvantage of such systems is that various magnetic interactions or effects can lead to inaccuracies or errors in the angle determination. Angular errors are essentially caused by two factors. On the one hand the magnetic reference is influenced by the magnetic field to be measured and does not remain rigid in the excellent direction, on the other hand the magnetization direction follows the Detection layer not free of errors or delays in the direction of the external magnetic field.
Aufgabe der Erfindung ist daher die Schaffung eines _ magnetoresistiven Sensorelements bzw. Sensors, mit dem auftretende Winkelfehler vermieden oder wenigstens verringert werden können.The object of the invention is therefore to create a magnetoresistive sensor element or sensor with which occurring angle errors can be avoided or at least reduced.
Diese Aufgabe wird gelöst durch ein magnetoresistives Sensorelement mit den Merkmalen des Patentanspruchs 1.This object is achieved by a magnetoresistive sensor element with the features of patent claim 1.
Erfindungsgemäß ist nun ein Sensorelement geschaffen, bei dem die Magnetisierungsrichtung der Detektionsschicht einem äußeren Magnetfeld, insbesondere auch bei betragsmäßig kleinem äußeren Magnetfeld, wesentlich leichter und genauer bzw. verzögerungsfreier folgen kann als dies bei herkömmlichen Sensorelementen möglich war. Die hierdurch erzielbare "Verbesserung der Genauigkeit des Sensorelements ist mit geringem technischen Aufwand (beispielsweise Strukturierung der Detektionsschicht durch bekannte chemische Verfahren) erreichbar.According to the invention, a sensor element is now created in which the direction of magnetization of the detection layer can follow an external magnetic field, in particular even with an external magnetic field that is small in terms of magnitude, much more easily and more accurately or more delay-free than was possible with conventional sensor elements. The " improvement in the accuracy of the sensor element that can be achieved in this way can be achieved with little technical effort (for example structuring of the detection layer by known chemical methods).
Vorteilhafte Ausgestaltungen des erfindungsgemäßen Sensorelements sind Gegenstand der Unteransprüche .Advantageous embodiments of the sensor element according to the invention are the subject of the dependent claims.
Es ist besonders bevorzugt, daß die Segmente wenigstens teilweise kreisförmig oder ellipsenförmig ausgebildet sind. Mit einer derartigen Formgebung erhält man eine besonders verzδgerungsfreie bzw. genaue Ausrichtung der Magnetisierungsrichtung der Detektionsschicht bezüglich eines äußeren Magnetfeldes. Zweckmäßigerweise weist das Sensorelement eine längliche bzw. langgestreckte Form auf. Durch diese Ausbildung wird eine weitgehende Unabhängigkeit der Referenzmagnetisierung von dem äußeren Magnetfeld erreicht . Durch die langgestreckte Form bzw. die Anisotropie des Sensorelements (seine Länge sollte wesentlich größer als seine Breite sein) ist insbesondere eine günstige Wirkung auf die Selbststabilisierung einer als künstlicher Antiferromagnet ausgebildeten Referenzschicht erzielbar.It is particularly preferred that the segments are at least partially circular or elliptical. With such a shape, a particularly delay-free or precise alignment of the direction of magnetization of the detection layer with respect to an external magnetic field is obtained. The sensor element expediently has an elongated or elongated shape. This design ensures that the reference magnetization is largely independent of the external magnetic field. The elongated shape or the anisotropy of the sensor element (its length should be significantly greater than its width) has a particularly favorable effect on the self-stabilization of a reference layer designed as an artificial antiferromagnet.
Als besonders vorteilhaft wird angesehen, die Sensorelemente mäanderförmig auszubilden. Hierdurch sind auf geringem Raum sehr lange Sensorstrukturen realisierbar.It is considered to be particularly advantageous to design the sensor elements in a meandering shape. As a result, very long sensor structures can be implemented in a small space.
Zweckmäßigerweise ist die erste Schicht eine hartmagnetische Schicht. Derartige Schichten sind preiswert realisierbar und gewährleisten eine gute magnetische Stabilität der Referenzschicht.The first layer is expediently a hard magnetic layer. Such layers are inexpensive to implement and ensure good magnetic stability of the reference layer.
Die dritte Schicht ist zweckmäßigerweise als weichmagnetische Schicht ausgebildet. Derartige Schichten sind in einfacher und preiswerter Weise in einer Vielzahl verschiedener Formen realisierbar. Als bevorzugtes Beispiel für weichmagnetische Werkstoffe seien Ni-Fe Legierungen genannt.The third layer is expediently designed as a soft magnetic layer. Such layers can be implemented in a variety of different forms in a simple and inexpensive manner. Ni-Fe alloys may be mentioned as a preferred example of soft magnetic materials.
Es ist bevorzugt, daß die erste Schicht aus einer Schichtanordnung mit einer selbststabilisierenden Kopplung (künstlicher Antiferromagnet) besteht. Derartige Schichten weisen eine besonders hohe magnetische Stabilität auf, ferner wirkt sich eine längliche Formgebung des Sensorelement auf die magnetische Stabilität derartiger Schichtanordnungen besonders günstig aus.It is preferred that the first layer consists of a layer arrangement with a self-stabilizing coupling (artificial antiferromagnet). Such layers have a particularly high magnetic stability, furthermore an elongated shape of the Sensor element on the magnetic stability of such layer arrangements particularly favorable.
Es ist ebenfalls bevorzugt, daß die erste Schicht eine künstlich gepinnte bzw. vorgespannte Magnetisierung aufweist. Eine derartige Magnetisierung ist beispielsweise mittels eines in Wirkverbindung mit der ersten Schicht stehenden stromdurchflossenen Leiters zur Stabilisierung ihrer Magnetisierungsrichtung erzielbar.It is also preferred that the first layer has an artificially pinned or biased magnetization. Such magnetization can be achieved, for example, by means of a current-carrying conductor which is in operative connection with the first layer in order to stabilize its direction of magnetization.
Es ist bevorzugt, daß die erste und dritte Schicht unter Verwendung von GMR-Werkstoffen hergestellt sind.It is preferred that the first and third layers are made using GMR materials.
Die Erfindung wird nun anhand einer bevorzugten Ausführungsform unter Bezugnahme auf die beigefügte Zeichnung im einzelnen erläutert . In dieser zeigtThe invention will now be explained in detail using a preferred embodiment with reference to the accompanying drawings. In this shows
Figur 1 eine schematische Draufsicht einer bevorzugten Ausführungsform des erfindungsgemäßen Sensorelements, undFigure 1 is a schematic plan view of a preferred embodiment of the sensor element according to the invention, and
Figur 2 das Sensorelement der Figur 1 schematisch in einer SeitenansichtFigure 2 shows the sensor element of Figure 1 schematically in a side view
Das in Figur 1 dargestellte Sensorelement weist eine erste, magnetische bzw. magnetisierte Schicht 1 auf, welche eine Referenzschicht darstellt . Der innere Aufbau dieser ersten Schicht ist nicht im einzelnen dargestellt. Es ist bevorzugt, daß die erste Schicht 1 als künstlicher Antiferromagnet ausgebildet ist, d.h. zwischen zwei dünnen magnetischen Lagen mit (im Grundzustand) antiparallel ausgerichteten Magnetisierungen ist eine als antiferromagnetische Kopplungschicht wirkende, dünne metallische Zwischenschicht ausgebildet . Bezüglich der magnetischen Rahmenbedingungen, die zur Schaffung eines selbststabilierenden künstlichen Antiferromagneten _ notwendig sind, wird auf den bereits erwähnten Artikel von van den Berg et. al . verwiesen.The sensor element shown in FIG. 1 has a first, magnetic or magnetized layer 1, which represents a reference layer. The internal structure of this first layer is not shown in detail. It is preferred that the first layer 1 is designed as an artificial antiferromagnet, ie between two thin magnetic layers with (in the basic state) antiparallel oriented magnetizations as antiferromagnetic coupling layer acting thin metallic intermediate layer. Regarding the magnetic framework necessary for the creation of a self-stabilizing artificial antiferromagnet, reference is made to the article by van den Berg et. al. directed.
Die Richtung der durch die erste Schicht 1 geschaffenen Referenzmagnetisierung ist in Figur 1 und Figur 2 durch einen Pfeil 5 dargestellt. Die zu messende Richtung eines äußeren Magnetfeldes ist durch den gestrichelten Pfeil 6 dargestellt .The direction of the reference magnetization created by the first layer 1 is shown in FIG. 1 and FIG. 2 by an arrow 5. The direction of an external magnetic field to be measured is shown by the dashed arrow 6.
Auf die erste Schicht 1 ist eine dünne, unmagnetische zweite Schicht 2 aufgebracht, auf welcher wiederum eine magnetische dritte Schicht 3 (Detektionsschicht) ausgebildet ist.A thin, non-magnetic second layer 2 is applied to the first layer 1, on which in turn a magnetic third layer 3 (detection layer) is formed.
Das SchichtSystem mit den Schichten 1, 2, 3 wird vorteilhafterweise in der schematisch dargestellten langgezogenen (oder auch einer mäandrierten) Form hergestellt, wobei zunächst auch die dritte Schicht 3 unstrukturiert, d.h. entsprechend den Schichten 1, 2 ausgebildet ist. Anschließend wird die dritte Schicht 3 beispielsweise mittels chemischer Verfahren (z.B.The layer system with the layers 1, 2, 3 is advantageously produced in the schematically illustrated elongated (or also a meandered) form, the third layer 3 also initially being unstructured, i.e. is formed according to layers 1, 2. The third layer 3 is then removed, for example by means of chemical processes (e.g.
Ätzverfahren) in Form der dargestellten Ellipsen 3a oder in Form von Kreisen selektiv strukturiert. Eine derartige Strukturierung erweist sich für die Sensorfunktion als sehr günstig, da hierdurch die Magnetisierungsrichtung auch betragsmäßig kleinen äußeren Magnetfeldern verhältnismäßig leicht folgen kann. Die (der Richtung 6 des äußeren Magnetfeldes entsprechende) Magnetisierung ist mittels Pfeilen 7 für die jeweiligen Ellipsen 3a dargestellt.Etching process) in the form of the illustrated ellipses 3a or in the form of circles selectively structured. Structuring of this type proves to be very favorable for the sensor function, since this means that the direction of magnetization can also follow relatively small external magnetic fields with relative amounts. The (the direction 6 of the outer Magnetization corresponding to the magnetic field is represented by arrows 7 for the respective ellipses 3a.
Bei Anlegen einer Spannung an die jeweiligen Enden 10, 11 des Sensorelements ergibt sich, in Abhängigkeit von einem anliegenden äußeren Magnetfeld, ein charakteristischer Widerstandswert des Sensorelements, aus welchem der Winkel der Magnetisierungsrichtung des äußeren Feldes bestimmbar ist.When a voltage is applied to the respective ends 10, 11 of the sensor element, a characteristic resistance value of the sensor element results, depending on an applied external magnetic field, from which the angle of the magnetization direction of the external field can be determined.
Die erfindungsgemäßen Sensorelemente können in an sich bekannter Weise beispielsweise zu Brückenschaltungen verschaltet werden. Mit Sensoren, die derartige Brückenschaltungen verwenden, sind Winkelmessungen in besonders einfacher und zuverlässiger Weise möglich. The sensor elements according to the invention can be connected, for example, to bridge circuits in a manner known per se. With sensors that use such bridge circuits, angle measurements are possible in a particularly simple and reliable manner.

Claims

Ansprüche Expectations
1. Magnetoresistives Sensorelement, insbesondere Winkelsensorelement, mit einer ersten, magnetischen Schicht1. Magnetoresistive sensor element, in particular angle sensor element, with a first, magnetic layer
(1) , deren Magnetisierungsrichtung eine Referenzrichtung darstellt, einer auf der ersten Schicht (1) ausgebildeten zweiten, nicht-magnetischen Schicht (2) , und einer dritten, auf der zweiten Schicht ausgebildeten magnetischen Schicht(1) whose direction of magnetization is a reference direction, a second non-magnetic layer (2) formed on the first layer (1), and a third magnetic layer formed on the second layer
(3), deren Magnetisierungsrichtung durch ein äußeres(3), whose direction of magnetization by an external
Magnetfeld beeinflußbar ist, d a d u r c h g e k e n n z e i c h n e t , daß die dritte Schicht (3) wenigstens teilweise in Form von einzelnen Segmenten (3a) ausgebildet ist.Magnetic field can be influenced, so that the third layer (3) is at least partially in the form of individual segments (3a).
2. Sensorelement nach Anspruch 1, dadurch gekennzeichnet, daß die Segmente (3a) wenigstens teilweise kreisförmig oder ellipsenförmig ausgebildet sind.2. Sensor element according to claim 1, characterized in that the segments (3a) are at least partially circular or elliptical.
3. Sensorelement nach einem der Ansprüche 1 oder 2, dadurch gekennzeichnet, daß es eine längliche Form aufweist. 3. Sensor element according to one of claims 1 or 2, characterized in that it has an elongated shape.
4. Sensorelement nach einem der vorstehenden Ansprüche, dadurch gekennzeichnet, daß es mäanderförmig ausgebildet ist.4. Sensor element according to one of the preceding claims, characterized in that it is meandering.
5. Sensorelement nach einem der vorstehenden Ansprüche, dadurch gekennzeichnet, daß die erste Schicht (1) eine hartmagnetische Schicht ist.5. Sensor element according to one of the preceding claims, characterized in that the first layer (1) is a hard magnetic layer.
6. Sensorelement nach einem der vorstehenden Ansprüche, dadurch gekennzeichnet, daß die dritte Schicht (3) eine weichmagnetische Schicht ist.6. Sensor element according to one of the preceding claims, characterized in that the third layer (3) is a soft magnetic layer.
7. Sensorelement nach einem der vorstehenden Ansprüche, dadurch gekennzeichnet, daß die erste Schicht (1) aus einer Schichtanordnung mit einer selbststabilisierenden Kopplung besteht .7. Sensor element according to one of the preceding claims, characterized in that the first layer (1) consists of a layer arrangement with a self-stabilizing coupling.
8. Sensorelement nach einem der vorstehenden Ansprüche, dadurch gekennzeichnet, daß die erste Schicht (1) eine künstlich gepinnte Magnetisierung aufweist.8. Sensor element according to one of the preceding claims, characterized in that the first layer (1) has an artificially pinned magnetization.
9. Sensorelement nach einem der vorstehenden Ansprüche, dadurch gekennzeichnet, daß die erste und/oder die dritte Schicht (1,3) unter Verwendung von GMR-Werkstoffen hergestellt ist bzw. sind. 9. Sensor element according to one of the preceding claims, characterized in that the first and / or the third layer (1,3) is or are produced using GMR materials.
EP99924763A 1998-09-22 1999-04-03 Magnetoresistive sensor element, especially angular sensor element Withdrawn EP1046046A1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DE1998143349 DE19843349A1 (en) 1998-09-22 1998-09-22 Magneto-resistive sensor element for measurement of external magnetic field angle, especially in bridge circuits, has outer sensor layer comprised partially or completely of individual segments
DE19843349 1998-09-22
PCT/DE1999/001013 WO2000017666A1 (en) 1998-09-22 1999-04-03 Magnetoresistive sensor element, especially angular sensor element

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DE10255327A1 (en) * 2002-11-27 2004-06-24 Robert Bosch Gmbh Magnetoresistive sensor element and method for reducing the angular error of a magnetoresistive sensor element
JP5590349B2 (en) 2012-07-18 2014-09-17 Ｔｄｋ株式会社 Magnetic sensor system
US10096767B2 (en) * 2013-03-09 2018-10-09 Taiwan Semiconductor Manufacturing Company, Ltd. Elongated magnetoresistive tunnel junction structure

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US5452163A (en) * 1993-12-23 1995-09-19 International Business Machines Corporation Multilayer magnetoresistive sensor
DE19507303A1 (en) * 1995-03-02 1996-09-05 Siemens Ag Sensor device with a bridge circuit of magnetoresistive sensor elements
JP3886589B2 (en) * 1997-03-07 2007-02-28 アルプス電気株式会社 Giant magnetoresistive element sensor

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AU4132399A (en) 2000-04-10

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