Sensor element for storing revolution or position information and memory system

Abstract

The invention relates to a sensor element (1; 1') comprising a domain wall conductor (1.1; 1.1') arranged on a substrate (1.2), wherein the course of the domain wall conductor is designed without crossings and the domain wall conductor comprises a first region (A) with a positive curvature and a second region (B) with a negative curvature. Furthermore the sensor element comprises an electrically conductive layer (1.7) applied on the substrate (1.2) and arranged overlapping and electrically insulated with respect to the domain wall conductor. The electrically conductive layer has at least two contact sites (1.71, 1.72, 1.73, 1.74) which are arranged in such a way that by applying a voltage on the at least two contact sites an electric current can flow in a first current direction, so that a domain wall (W1, W2, W1', W2') can be generated in the domain wall conductor by a magnetic field of the electric current.

Description

Technical Field

[0001] The present invention relates to a sensor element for storing rotation information or position information, for example, for an angle or length measuring device, and a memory system having the sensor element. Background Technology

[0002] Angle measuring devices are used, for example, as rotary encoders to determine the angular position of two machine parts that can rotate relative to each other. For this purpose, so-called multi-turn angle measuring devices are often used, by which absolute position measurement across multiple revolutions can be achieved.

[0003] Furthermore, length measuring devices are known that measure the linear displacement of two machine parts that can be displaced relative to each other. Particularly when the length measuring device has a large measuring length, multiple linear scales or identical graduations are typically arranged side-by-side. In the case of such a length measuring device, it is necessary to achieve absolute position determination over the entire measuring length as much as possible.

[0004] Such measuring devices or equipment for electric actuators are typically used to determine the relative movement or relative position of corresponding machine parts. In this case, the resulting position values ​​are transmitted via a corresponding interface device to subsequent electronic equipment for controlling the actuator.

[0005] For many applications of position measuring devices, especially angle or length measuring devices, it is important that the number of revolutions or a rough position be stored in a non-volatile manner.

[0006] EP 1 740 909 B1 describes a sensor element for a tachometer, wherein domain walls are formed, and the sensor element has a special helical shape. Summary of the Invention

[0007] The objective of this invention is to create a sensor element that includes domain wall conductors and enables initialization or reset in an economical structural configuration.

[0008] According to the present invention, this task is accomplished by a sensor element used to store rotation information or position information.

[0009] Therefore, the present invention relates to a sensor element for actively storing revolutions or position information, particularly aktiv. The sensor element includes domain wall conductors disposed on a substrate, wherein the orientation of the domain wall conductors is designed to be non-intersecting. The domain wall conductors or their orientation further include a first region having positive curvature and a second region having negative curvature. Furthermore, the sensor element includes a conductive layer applied to the substrate and disposed overlapping and electrically insulatingly relative to the domain wall conductors. The conductive layer has at least two contact points. These contact points are arranged such that applying a voltage to the at least two contact points causes current to flow in a first current direction, thereby enabling the generation of domain walls in the domain wall conductors by the magnetic field of the current.

[0010] Therefore, the conductive layer is arranged versetically relative to the domain wall conductor in a direction orthogonal to the substrate layer in an electrically insulating manner. The conductive layer thus electrically and completely or only partially covers the domain wall conductor. In particular, the domain wall conductor can be applied onto the insulating layer, wherein the conductive layer is applied across the entire surface of the opposite side of the insulating layer.

[0011] The term "active storage" should be understood as storage in which the sensor element in question does not require any auxiliary electrical power.

[0012] Advantageously, the orientation of the domain wall conductor is designed to be axially symmetric about an axis. Here, the axis can be oriented at an angle relative to the first current direction, or the current direction can extend at an angle inclined to the axis. Specifically, the angle formed by the current direction and the axis is greater than 10° and less than 60° (10° < β < 60°), advantageously greater than 15° and less than 50° (15° < β < 50°). Thus, the axis and the current direction form an angle in the conductive layer, for example, between 10° and 60°, where the smaller of the supplementary angles is referred to here.

[0013] In conjunction with this invention, domain wall conductors, particularly conductor tracks or conductor lines (Leiterbahn) or nanowires, are composed of magnetizable materials. Information can be stored in the domain wall conductors in the form of oppositely magnetized regions (domains). These domains are separated by so-called domain walls, which can be shifted (verschieben) by a magnetic field, thus changing the position of the domains. To determine the position of the domains, readout elements are arranged such that the domains or domain walls pass beside the readout elements. Therefore, functionally, the domain wall conductor can also be considered a type of shift register.

[0014] Advantageously, the orientation of the domain wall conductors is designed to be closed and encircling. Alternatively, the orientation of the domain wall conductors can also be designed to be continuous.

[0015] The domain wall conductor's orientation forms a continuous curve, without abrupt changes, peaks, Knicke's points, or other discontinuities. Therefore, the term "continuous orientation" should be understood as the domain wall conductor's orientation being designed to be uniform without sudden changes in direction. Mathematically, the domain wall conductor's orientation is continuous and, in particular, differentiable over its entire length, thus producing a distinct tangent at every point along its orientation. Specifically, the domain wall conductor has only radii of curvature greater than 0.005 mm, particularly greater than 0.02 mm, and advantageously greater than 0.03 mm along its orientation.

[0016] The non-intersecting orientation of domain wall conductors should be understood in particular as meaning that the orientations of the domain wall conductors do not intersect, but are not guided in overlapping manner in different layers.

[0017] Curvature should be understood as the directional variation along the orientation of a domain wall conductor on a particularly flat substrate. In the case of a straight orientation, the curvature is equal to 0 because the orientation direction does not change. If the curvature is not equal to 0, the orientation of the domain wall conductor can be defined as having a positive or negative sign with respect to the orientation of the normal bundle of the orientation curve. If the curvature bends in the direction of the unit normal vector field, the curvature is positive, and if the curvature bends in the opposite direction, the curvature is negative. For example, a first region with positive curvature can be called a convex region, and a second region with negative curvature can be called a concave region. Therefore, mathematically speaking, the orientation of a domain wall conductor thus has at least one inflection point.

[0018] According to an advantageous variation, the sensor element further includes a readout element by which the local magnetization state of the domain wall conductor can be determined (at a corresponding position of the readout element). Therefore, the magnetization state of the domain wall conductor can be determined individually by the readout element. The readout element is fixedly arranged relative to the domain wall conductor.

[0019] In another embodiment of the invention, the domain wall conductor is disposed in a layer between at least one of the readout elements and the substrate. Alternatively or additionally, at least one of the readout elements is disposed in a layer between the substrate and the domain wall conductor.

[0020] Advantageously, the readout element is designed as a GMR or TMR sensor.

[0021] The sensor element may have multiple domain wall conductors. In this case, the multiple domain wall conductors may have different numbers of first regions or different numbers of second regions. Thus, for example, the sensor element may have a first domain wall conductor and a second domain wall conductor, wherein the first domain wall conductor has a first number of first regions and the second domain wall conductor has a second number of first regions.

[0022] Advantageously, these distinct numbers, namely the number of first regions of the first domain wall conductor and the number of first regions of the second domain wall conductor, are coprime. As is well known, the term "coprime" should be understood as meaning that for the numbers (natural numbers) in question, there is no other natural number besides one that divides both numbers evenly.

[0023] Advantageously, the conductive layer has four contact points arranged such that a voltage can be applied to two pairs of contact points, thereby allowing current to flow selectively in either a first current direction or a second current direction. According to an advantageous, simple arrangement, the first current direction corresponds to the direction of the connecting line between the first and second contact points. Alternatively or supplementarily, the second current direction may correspond to the direction of the connecting line between the third and fourth contact points.

[0024] In another design of the present invention, the first current direction is orthogonally oriented to the second current direction.

[0025] According to another aspect, the present invention includes a memory system having a sensor element, a component, and a supporting magnet. The component includes a magnet assembly and is designed to be movable relative to a domain wall conductor in a first direction. The supporting magnet is immovably arranged relative to the sensor element, specifically such that the sensor element is positioned between the magnet assembly and the supporting magnet. Alternatively, the supporting magnet is movably arranged relative to the sensor element on the component, adjacent to the magnet assembly, with respect to the first direction. Furthermore, the supporting magnet is configured such that the domain wall conductor can be initialized by a magnetic field of the supporting magnet superimposed on an induced magnetic field of a conductive layer.

[0026] The component can be designed, for example, as a roller with angular markings or as a length scale.

[0027] The displacement of the magnetic domain or domain wall is caused by the movement of the magnet device relative to the domain wall conductor in the first direction.

[0028] Advantageously, the supporting magnet is arranged such that the connecting line between the north pole and the south pole of the supporting magnet is oriented in a second direction, wherein the second direction is oriented such that it has a component orthogonal to the first direction. Specifically, the connecting line extends in a layer or plane parallel to the substrate.

[0029] Both the magnet and the supporting magnet of the magnet device are specifically designed as permanent magnets.

[0030] Advantageously, the sensor element includes a particularly flat substrate and the domain wall conductor is designed as a conductor line on the substrate.

[0031] In another design of the invention, the width of the domain wall conductor is less than 1000 nm, particularly less than 500 nm, and advantageously less than 300 nm.

[0032] The thickness or layer thickness of the domain wall conductor is advantageously less than 200 nm, particularly less than 150 nm, and especially less than 60 nm.

[0033] Advantageously, the substrate has a glass layer and / or a silicon layer. In particular, when the substrate has a silicon layer, the sensor element can be incorporated as part of a CMOS chip.

[0034] Advantageously, the sensor element and the support magnet are arranged in a common housing.

[0035] Advantageously, the magnetic field generated by the magnet device is designed to be asymmetrical with respect to an axis extending parallel to the first direction. This consideration applies to any imaginary axis extending parallel to the first direction.

[0036] Advantageously, in another embodiment of the invention, the magnetic field generated by the magnet device is designed to be symmetrical about an axis extending parallel to the second direction. Here, the second direction is orthogonal to the first direction.

[0037] The axis extending parallel to the first direction and the axis extending parallel to the second direction are particularly located in the layer oriented parallel to the substrate.

[0038] In another design of the memory system, the magnet device is designed as a magnet array having magnets whose magnetic poles are arranged offset from each other in the first direction.

[0039] Advantageously, the orientation of the domain wall conductor is designed to be axisymmetric. In particular, the axis of symmetry may be parallel to or extend in the second direction.

[0040] The domain wall conductor has a dimension in the first direction, and the two magnetic poles have a center distance, wherein the dimension is less than the center distance. Here, the maximum dimension of the domain wall conductor should be understood in particular in the first direction. The center distance can be specifically the distance between the effective centers of the magnet. For example, in the case of a cylindrical bar magnet, the center distance can be considered as the distance between the longitudinal axes of the cylindrical bar magnet.

[0041] The memory system is designed to have at least two domain walls, although designs with four or more domain walls may also be used.

[0042] The memory system can be used in conjunction with an angle measuring device, where the rotation count is stored in particular. Alternatively, the memory system or the sensor element can be used in conjunction with a linear scale. The scale can, in particular, include a first scale section and a second scale section. The first and second scale sections can be arranged side-by-side, for example, along the first direction, thereby enabling a larger measurement length. In practice, it is also entirely possible to arrange more than two scale sections side-by-side. A magnet device is then positioned offset from each other along the first direction. The sensor element can store corresponding position information, thereby determining which scale section is currently being scanned.

[0043] Advantageous designs of the invention can be found in other embodiments.

[0044] Further details and advantages of the sensor according to the invention will emerge from the following description of embodiments based on the accompanying drawings. Attached Figure Description

[0045] Figure 1a A top view of the sensor element is shown. Figure 1b A side view of the sensor element is shown. Figure 2 A detailed view of the domain wall conductors is shown. Figure 3 The magnet of the magnet device is shown. Figure 4 A top view of the magnet device according to the first embodiment is shown. Figure 5 A side view of a component with a magnet assembly is shown. Figure 6 A top view of the component and the sensor element is shown. Figure 7 A schematic diagram is shown showing the domain wall conductor, the supporting magnet, and the magnet assembly in a first relative position relative to each other. Figure 8 A schematic diagram is shown showing the domain wall conductor, the supporting magnet, and the magnet assembly in a second relative position to each other. Figure 9 A schematic diagram is shown showing the domain wall conductor, the supporting magnet, and the magnet assembly in a third relative position relative to each other. Figure 10 A schematic diagram is shown showing the domain wall conductor, the supporting magnet, and the magnet assembly in a fourth relative position with respect to each other. Figure 11 A schematic diagram is shown showing the domain wall conductor, the supporting magnet, and the magnet assembly in a fifth relative position with respect to each other. Figure 12 A schematic diagram is shown showing the domain wall conductor, the supporting magnet, and the magnet assembly in a sixth relative position relative to each other. Figure 13 A schematic diagram is shown showing the domain wall conductor, the supporting magnet, and the magnet assembly in a seventh relative position relative to each other. Figure 14 A schematic diagram is shown showing the domain wall conductor, the supporting magnet, and the magnet assembly in an eighth relative position with respect to each other. Figure 15 A schematic diagram is shown showing the domain wall conductor, the supporting magnet, and the magnet assembly in a ninth relative position relative to each other. Figure 16 A schematic diagram of a sensor element having additional domain wall conductors and magnet devices according to a second embodiment is shown. Figure 17 A schematic diagram of the domain wall conductors during the first stage of the initialization or reset process is shown. Figure 18 A schematic diagram of the domain wall conductors during the second phase of the initialization or reset process is shown. Figure 19 A schematic diagram of the domain wall conductors in the third stage of the initialization or reset process is shown. Figure 20 A top view of the magnet device according to the third embodiment is shown. Figure 21 A schematic diagram shows the domain wall conductor, the supporting magnet, and the magnet device according to the third embodiment in a first relative position relative to each other. Figure 22 A schematic diagram of the domain wall conductors is shown in a further stage of the initialization or reset process. Figure 23 A schematic diagram of the domain wall conductor is shown after a further stage of the initialization or reset process. Figure 24 A side view of a component having a magnet device and a supporting magnet according to a fourth embodiment is shown. Detailed Implementation

[0046] Figure 1a A sensor element 1 comprising a domain wall conductor 1.1 and a substrate 1.2 is shown. In the illustrated embodiment, the substrate 1.2 has a mechanically supported glass layer, wherein the substrate 1.2 is designed to be planar. Alternatively, the substrate 1.2 may have a silicon layer, thus the sensor element 1 can be designed as part of a CMOS chip. The sensor element 1 has a layer structure, which can be simplified and described below (see also...) Figure 1b A conductive layer 1.7 is applied on the substrate 1.2. The conductive layer 1.7 is designed to be a copper layer only a few μm thick. The conductive layer 1.7 has a first contact portion 1.71, a second contact portion 1.72, a third contact portion 1.73, and a fourth contact portion 1.74.

[0047] An electrically insulating layer 1.8 is present on the conductive layer 1.7. In the illustrated embodiment, the conductive layer 1.7 completely covers the electrically insulating layer 1.8 on the side facing away from the domain wall conductor 1.1. The domain wall conductor 1.1, in the form of a conductor line, is applied to the insulating layer 1.8. The conductive layer 1.7 is arranged completely below the domain wall conductor 1.1, such that the conductive layer 1.7 overlaps with the domain wall conductor 1.1. The term "overlap" expresses: with respect to a third direction z ( Figure 1b The conductive layer 1.7 and the domain wall conductor 1.1 are arranged stacked one on top of the other, even though they are separated by a thin insulating layer 1.8. The domain wall conductor 1.1 is electrically insulated from the conductive layer 1.7 by the insulating layer 1.8.

[0048] Alternatively, the layer structure can be constructed in the opposite manner, i.e., a domain wall conductor 1.1 is applied to a substrate 1.2 and an insulating layer 1.8 is applied to the domain wall conductor 1.1, and a conductive layer 1.7 is applied to the insulating layer 1.8.

[0049] Domain wall conductor 1.1 comprises a soft magnetic material, such as a Ni-Fe alloy. Domain wall conductor 1.1 includes a first portion 1.11 and a second portion 1.12, wherein the domain wall conductor 1.1 extends in the first portion 1.11 as a relatively narrow bend, and the domain wall conductor 1.1 extends in the second portion 1.12 as an arc with a relatively large radius. The first portion 1.11 and the second portion 1.12 are directly adjacent, such that the orientation of the domain wall conductor 1.1 is designed as a closed loop. The domain wall conductor 1.1 is designed symmetrically about an axis C, which is oriented perpendicular to a first direction x and parallel to a second direction y. The domain wall conductor 1.1 has a width X1 in the first direction x.

[0050] Figure 2A segment of the domain wall conductor 1.1 is shown. It can be clearly seen here that the orientation of the domain wall conductor 1.1 includes a first region A with positive curvature and a second region B with negative curvature. In other words, if one follows the orientation of the domain wall conductor 1.1, one will encounter both sections with right-hand bends and sections with left-hand bends. In the orientation of the first section 1.11, the first region A with positive curvature is followed by the second region B with negative curvature, then the first region A again, and so on, wherein in the illustrated embodiment, there is a region with a straight orientation of the domain wall conductor 1.1 between the first region A and the second region B. In the second section 1.12, the sign of the curvature does not change. In the illustrated embodiment, the curvature or radius of curvature is designed to be constant there.

[0051] In the layer structure on substrate 1.2, according to Figure 1a There is a readout element 3 near the domain wall conductor 1.1. This readout element can be, for example, a GMR sensor or a TMR sensor. The magnetization state of the adjacent domain wall conductor can be determined by means of the readout element 3.

[0052] If a magnetic field moving relative to domain wall conductor 1.1 is properly applied to domain wall conductor 1.1, then domain walls W1 and W2 will shift within or along domain wall conductor 1.1. To generate a suitable magnetic field, a magnet device 1.3 is used. Figure 4 In the illustrated embodiment, the magnet device is designed as a magnet array consisting of a plurality of (permanent) magnets 1.31 to 1.33.

[0053] The first magnet 1.31 of the magnet device 1.3 is arranged such that there is magnetization parallel to the second direction y, or the north pole of the first magnet 1.31 is arranged offset relative to its south pole with respect to the second direction y. The second magnet 1.32 of the magnet device 1.3 is arranged offset relative to the first magnet 1.31 by a distance of 1 / 2∙X² in the first direction x. The third magnet 1.33 is placed opposite to the first magnet 1.31 offset in the first direction x. In the illustrated embodiment, the second magnet 1.32 and the third magnet 1.33 are designed to be identical. Therefore, magnets 1.32 and 1.33 are designed as cylinders, wherein the magnetic poles are arranged along the longest axis of symmetry in the sense of a bar magnet.

[0054] Exemplarily for the second magnet 1.32 and the third magnet 1.33 in Figure 3 The second magnet 1.32 is shown in the figure.

[0055] according to Figure 1a, the domain wall conductor 1.1 has a dimension X1 in the first direction x. The magnitude of the distance X2 between the center of the first magnet 1.31 and the center of the second magnet 1.32 is determined such that the dimension X1 is smaller than the distance X2, i.e., X1<X2 (related to the center distance of the first and second magnets 1.31, 1.32).

[0056] The magnet device 1.3 is usually fixed to the component 2 or the measuring standard. According to this embodiment, the component 2 has a substantially annular drum 2.1 (see Figure 5 , Figure 6 ). The magnet device 1.3 composed of the first, second and third magnets 1.31, 1.32, 1.33 is mounted on its outer circumference. Offset relative thereto in the second direction y, that is, in the axial direction, a fine scale 2.12 is applied to the outer circumference of the drum 2.1 in the illustrated embodiment. Alternatively, the magnet device 1.3 can also be arranged on the inner circumference of the drum or the hollow shaft. In addition to the second magnet 1.32 and the third magnet 1.33, further magnets can also be placed, which cause homogenization of the overall magnetic field. These measures reduce the susceptibility of the memory system to external magnetic fields and allow greater distance tolerances between the component 2 and the sensor element 1.

[0057] According to Figure 6 , the sensor element 1, that is, the domain wall conductor 1.1 having the substrate 1.2, is arranged in the housing 1.5 with a radial air gap relative to the drum 2.1, in particular the magnet device 1.3. The housing 1.5 is positionally fixed in the illustrated embodiment, while the component 2 with the magnet device 1.3 is rotatably supported, such that when the component 2 rotates in the first direction x (or vice versa), the magnet device 1.3 moves relative to the sensor element 1. The scale 2.12 can be decoded, for example, by an optical scanner, which can also be accommodated in the housing 1.5.

[0058] Furthermore, according to the first embodiment, a support magnet 1.6 is also present in the housing 1.5, which is arranged immovably relative to the sensor element 1. The sensor element 1 is arranged directly opposite to the movable magnet device 1.3, and the support magnet 1.6 is arranged behind the sensor element 1, thereby positioning the sensor element 1 between the magnet device 1.3 and the support magnet 1.6. The first magnet 1.31 is magnetized such that the line connecting its north and south poles is oriented parallel to the second direction y or parallel to the axis C. The support magnet 1.6 is arranged such that its magnetization is antiparallel to the magnetization of the first magnet 1.31. Therefore, the line connecting the north and south poles of the support magnet 1.6 also extends parallel to the second direction y, but with opposite pole orientations (in the figures, the north pole of the first magnet 1.31 is above, while the north pole of the support magnet 1.6 is below).

[0059] Figure 7 The schematic diagram shows the magnet assembly 1.3, the domain wall conductor 1.1, and the supporting magnet 1.6 behind them in a first position relative to each other. The magnetic field should be indicated by numerous arrows. In the first position (Stellung), the domain walls W1 and W2 are located according to... Figure 7 The positions of the domain walls, where (as indicated by symbols) the first domain wall W1 is the so-called head-to-head domain wall and the second domain wall W2 is the so-called tail-to-tail domain wall.

[0060] The magnetic field generated by magnet device 1.3 is designed to be about axis Ax ( Figure 4 and Figure 7 The first direction (Ax) is asymmetrical, with the axis Ax extending parallel to the first direction x. Conversely, the magnetic field 1.3 generated by this magnet device is designed to be symmetrical about the axis Ay, which extends parallel to the second direction y. Here, the second direction is orthogonal to the first direction.

[0061] If now the magnet device 1.3 is in the first direction x according to Figure 7 When the arrow moves relative to the domain wall conductor 1.1 (and therefore also relative to the substrate 1.2 and the supporting magnet 1.6), a quasi-rotational magnetic field acts on the domain wall conductor 1.1. As a result, the domain walls W1 and W2 are displaced. This displacement field is generated by the magnet device 1.3 passing beside the domain wall conductor 1.1, wherein the magnetic field of the magnet device 1.3 is superimposed on the magnetic field of the supporting magnet 1.6.

[0062] Figure 8 A domain wall conductor 1.1 is shown in a different location, where the magnetic field moves relative to the first location in the first direction x. Therefore, the domain walls W1 and W2 change their positions.

[0063] Similarly, since the magnet device 1.3 is relative to the domain wall conductor 1.1 along the first direction x ( Figure 9 , Figure 10 , Figure 11 Further displacement occurred, and the positions of domain walls W1 and W2 were further shifted. According to... Figure 11 The positions of domain walls W1 and W2 include, for example, the following information: roller 2.1 or component 2 and... Figure 7 The arrangement has been moved so far that the magnet device 1.3 completely passes over the domain wall conductor 1.1, for example, after the first rotation has completely ended. In particular, the domain walls W1 and W2 are displaced beyond the second part 1.12 by the magnetic fields of the first and second magnets 1.32 and 1.33, in which the domain wall conductor 1.1 extends in an arc with a large radius.

[0064] As component 2 moves or rotates further in the same direction, the positions of domain walls W1 and W2 remain unchanged temporarily. This is because the domain wall conductor 1.1 is always under the influence of the magnetic field of the supporting magnet 1.6, which is arranged so that it cannot move relative to the sensor element 1.

[0065] In the illustrated embodiment, the roller 2.1 or component 2 should rotate further in the same direction (first direction x), therefore in Figures 12 to 15 In the diagram, the different positions of domain walls W1 and W2 are shown, depending on the positioning of the magnet device 1.3 relative to the domain wall conductor 1.1 or relative to the sensor element 1.

[0066] After each pass of the magnet device 1.3 past the sensor element 1 or after each rotation of the component 2, the domain wall W1 has moved further to the adjacent first region A of the domain wall conductor 1.1. Correspondingly, after each rotation, the domain wall W2 has moved further from the second region B to the adjacent second region B of the domain wall conductor 1.1, or the domain wall W2 is located in the second portion 1.12, in which the domain wall conductor 1.1 extends in an arc with a larger radius. When the starting point is on an arc with a larger radius, the domain wall W2 moves into the arc in the second region B. According to... Figure 1a Given the arrangement, it can be counted that there are five consecutive passes or turns in one direction.

[0067] The magnetization direction within these portions of the domain wall conductor 1.1 can be detected by the readout element 3, and thus the approximate positions of the domain walls W1 and W2 can be detected. In this way, even without auxiliary energy, the number of revolutions can be counted or the revolution information can be stored in the angle measuring device. This is important, for example, when the shaft moves due to weight load, such as when the current is interrupted. Furthermore, the domain walls W1 and W2 also shift according to the direction of rotation, so that the sensor element 1 can be reliably used in applications that allow two directions of rotation.

[0068] Important for the function of the memory system is that, as the magnet device 1.3 passes by along the first direction x, the magnetic field acts on the domain wall conductor 1.1, and the direction of this magnetic field changes depending on the position of x. Specifically, there are quasi-rotating or rotating magnetic field lines or directions. Axis Ay ( Figure 7 The magnetic field lines on one side of axis Ay have opposite directions of rotation compared to the magnetic field lines on the other side. In particular, the magnetic field lines covering region A during traversal have opposite directions of rotation compared to the magnetic field lines covering region B during traversal.

[0069] according to Figure 16 In a second embodiment, the sensor element 1' may include a plurality of domain wall conductors 1.1, 1.1' to increase the number of countable revolutions, wherein the domain wall conductors 1.1, 1.1' have, for example, first domain walls W1, W1' and second domain walls W2, W2', respectively. In this case, it is advantageous that the plurality of domain wall conductors 1.1, 1.1' have different numbers of first portions 1.11, 1.11', particularly different numbers of first regions A or different numbers of second regions B. When using a plurality of domain wall conductors 1.1, 1.1', it is advantageous that the number of first regions A of the respective domain wall conductors 1.1, 1.1' is coprime. The plurality of domain wall conductors 1.1, 1.1' may be arranged offset from each other or nested within each other in the first direction x. Figure 16 In the design, domain wall conductors 1.1 and 1.1' are designed such that these domain wall conductors have four and five first regions A, respectively, where, for clarity, in Figure 16 The diagram shows domain wall conductors 1.1 and 1.1' with a relatively small number of first regions A. In practice, it is suitable to use domain wall conductors with more than four first regions A. For example, four domain wall conductors with 7, 9, 11, or 13 first regions A can be used, thus allowing a count of 9009 (7 x 9 x 11 x 13) revolutions.

[0070] Before operation begins, i.e., during memory system initialization or reset, a predetermined number of domain walls should be directed to defined positions on domain wall conductors 1.1 and 1.1'. The initialization or reset process is performed at a location outside the influence area of ​​the magnet device 1.3. First, in the first process step, a voltage or potential difference is applied to the first contact portion 1.71 and the second contact portion 1.72, for example, by connecting a charged capacitor, causing the discharge current of the capacitor to then flow through the first contact portion 1.71 and the second contact portion 1.72. Therefore, current flows in the conductive layer 1.7 of the sensor element 1 in the first current direction. The current flows upwards, and the direction of this first current corresponds here to the direction of the connecting line between the first contact portion 1.71 and the second contact portion 1.72. From Figure 1a It can be seen that axis C is relative to the first flow direction The orientation is tilted at an angle β. In the illustrated embodiment, angle β is 25°. Therefore, the magnetic field induced by the current in the conductive layer 1.7 generates a large number of domain walls W1, W2 ( Figure 17 Here, the strength of the induced magnetic field is significantly greater than the nucleation magnetic field required to generate domain walls W1 and W2. Therefore, even if the sensor element 1 is permanently placed in the magnetic field of the supporting magnet 1.6, the current-induced magnetic field dominates during periods when current flows through it due to its high field strength. The current or current intensity in the conductive layer 1.7 must be chosen to be correspondingly large. Furthermore, this process requires only a very short time period. A current-induced magnetic field of less than 1 μs is sufficient, thereby avoiding overheating caused by the combination of the heat capacity and unstable thermal conduction of the sensor element 1, especially the substrate 1.2, even when a relatively high current flows through it for a short period of time. Figure 17 The seven large arrows in the diagram should represent the total magnetic field resulting from the superposition of the magnetic field generated by the magnetic field of the supporting magnet 1.6 and the magnetic field generated by the current in the conductive layer 1.7.

[0071] In the next step, the current flowing through the conductive layer 1.7 is disabled or interrupted, causing the domain wall conductor 1.1 to... Figure 18 The arrows in the diagram are still exposed to the magnetic field of the supporting magnet 1.6. As a result, head-to-head domain walls W1 and tail-to-tail domain walls W2 travel towards each other in the straight central region of the domain wall conductor 1.1. Figure 18 And ultimately they cancel each other out (auslöschen) Figure 19Then, the desired defined state is reached, in which the remaining first (head-to-head) domain walls W1 are located in the first region A, and the remaining second (tail-to-tail) domain walls W2 are located in the second region B. The initialization or reset of the domain wall conductor 1.1 is now complete. In particular, the support magnet 1.6 is thus configured such that the domain wall conductor 1.1 can be initialized by the magnetic field of the support magnet 1.6 superimposed on the magnetic field of the conductive layer 1.7.

[0072] exist Figure 20 A third embodiment is shown, which is particularly suitable for applications requiring only a small number of revolutions or traversals to be counted. In this case, the magnet device 1.3'' can be simplified to having only a first magnet 1.31. However, in this simplified device, the first domain wall W1 cannot move through the second portion 1.12 of the domain wall conductor 1.1 by means of the magnetic field generated by the magnet device 1.3''. Therefore, in this case, the number of countable revolutions or traversals is limited to the number of the first portion 1.11 of the domain wall conductor 1.1. In this embodiment, it is not necessary to design the orientation of the domain wall conductor as a closed loop. For example, the region with a large radius of curvature, i.e., the second portion of the domain wall conductor, can be omitted here, thus allowing the domain wall conductor to have two ends instead. Then, to stabilize the magnetization, a region with, for example, antiferromagnetic coupling is arranged there.

[0073] For only a relatively small number of revolutions or a few bypasses, in order to initialize the memory system or reset the domain wall conductor 1.1, the same steps as in the first embodiment are first performed. Correspondingly, the domain wall conductor 1.1 is in a defined state in which domain wall W1 is located in the first region A in the first portion 1.11, and the second domain wall W2 is located in the second portion 1.12, as per [the previous description of the domain wall conductor 1.12]. Figure 19 As shown. For sensor element 1 that is only used to count a small number of revolutions or a few passing by, it is advantageous that the first domain wall W1 is located as centrally as possible in the first region A or the first portion 1.11.

[0074] When sensor element 1 is outside the influence region of magnet device 1.3 but within the influence region of supporting magnet 1.6, the following process steps are also performed. To make the first domain wall W1... Figure 19 Starting from the position and shifting, a voltage or potential difference is now applied to the third contact 1.73 and the fourth contact 1.74. As a result, a current flows in the conductive layer 1.7 of the sensor element 1 in the second current direction. The current flows upward. The applied current intensity is now lower compared to the current previously generated between the first and second contact sites 1.71 and 1.72. However, the current is now maintained for a longer time (a few μs) than before. Then the domain walls W1 and W2 flow according to... Figure 22 The location. Figure 22 The seven large arrows in the diagram should represent the total magnetic field resulting from the superposition of the magnetic field generated by the magnetic field of the supporting magnet 1.6 and the magnetic field generated by the current in the conductive layer 1.7.

[0075] Then, the current is prohibited from flowing, thus leaving the domain wall conductor 1.1 exposed only to the magnetic field of the supporting magnet 1.6. Under these conditions, the domain walls W1 and W2 move according to... Figure 23 The location.

[0076] These last two process steps can now be repeated until the first domain wall W1 is located in the middle of the first region A and the second domain wall W2 is located in the middle of the second part 1.12. Then, in a state not explicitly shown in the figures, the domain walls W1 and W2 are located on axis C, and the maximum number of revolutions or the maximum number of times they pass by in both directions of movement can now be counted.

[0077] In the embodiments shown so far, the memory system is designed such that the support magnet 1.6 is arranged immovably relative to the sensor element 1, wherein the support magnet 1.6 is arranged such that the sensor element 1 is located between the magnet devices 1.3, 1.3'' and the support magnet 1.6.

[0078] According to the fourth embodiment, see Figure 24 A support magnet 2.11 is alternatively arranged on component 2''', which is otherwise designed similarly to the three embodiments. However, the magnet device 1.3''' here comprises a magnet array consisting of a plurality of (permanent) magnets. Furthermore, the roller 2.1''' has a support magnet 2.11 in its outer peripheral region. This support magnet 2.11 may, for example, consist of a layer of magnetizable material. Magnetization is performed such that the north and south poles are arranged axially offset from each other. A fine graduation 2.12 is also applied here, offset relative to the support magnet 2.11 in the second direction y, i.e., in the axial direction.

Claims

1. A sensor element (1; 1') for storing revolutions or position information, wherein the sensor element (1; 1'） -Including domain wall conductors (1.1; 1.1') disposed on a substrate (1.2), wherein the domain wall conductors (1.1; 1.1') The orientation of 1.1' is designed to be non-intersecting and to be axially symmetric about the axis (C), and the domain wall conductor (1.1; 1.1') includes a first region (A) with positive curvature and a second region (B) with negative curvature. - Includes a conductive layer (1.7) applied to the substrate (1.2) and disposed overlapping with and electrically insulatingly relative to the domain wall conductors (1.1; 1.1'), wherein the conductive layer (1.7) has at least two contact portions (1.71, 1.72, 1.73, 1.74), the contact portions being arranged such that, By applying a voltage to at least two contact points (1.71, 1.72, 1.73, 1.74), the current flows in the first current direction ( The current flows on the domain wall conductor (1.1; 1.1'), thereby enabling the generation of domain walls (W1, W2, W1', W2') in the domain wall conductor (1.1; 1.1') by the magnetic field induced by the current, wherein the axis (C) is perpendicular to the direction of the first current ( It is tilted at an angle (β) in a way that is oriented.

2. The sensor element (1; 1') according to claim 1, wherein, The angle (β) is greater than 10° and less than 60°.

3. The sensor element (1; 1') according to claim 1 or 2, wherein, The domain wall conductors (1.1; 1.1') are designed to be closed-loop.

4. The sensor element (1; 1') according to claim 1 or 2, wherein, The orientation of the domain wall conductors (1.1; 1.1') is designed to be continuous.

5. The sensor element (1; 1') according to claim 1 or 2, wherein, The sensor element (1; 1') also has a readout element (3) through which the local magnetization state of the domain wall conductor (1.1; 1.1') can be determined.

6. The sensor element (1; 1') according to claim 5, wherein, The readout element (3) is designed as a GMR or TMR sensor.

7. The sensor element according to claim 1 or 2, wherein, The sensor element has multiple domain wall conductors (1.1; 1.1'), which have different numbers of first regions (A) or different numbers of second regions (B).

8. The sensor element according to claim 7, wherein, The different numbers in the first region (A) are coprime.

9. The sensor element (1; 1') according to claim 1 or 2, wherein, The conductive layer (1.7) has four contact points (1.71, 1.72, 1.73, 1.74), which are arranged such that they can be connected at two pairs of contact points ( A voltage is applied to 1.71, 1.72, 1.73, 1.74, thereby selectively directing the current in the first current direction ( ). ) or the second current direction ( ) flows on.

10. The sensor element (1; 1') according to claim 9, wherein, The first current direction ( ) and the second current direction ( Orthogonal orientation.

11. A memory system comprising the sensor element (1; 1'), component (2), and supporting magnet (1.6, 2.11) according to claim 1, wherein - The component (2) includes a magnet device (1.3; 1.3''; 1.3'''), which is movable relative to the domain wall conductor (1.1; 1.1') in a first direction (x). -The supporting magnets (1.6, 2.11) -Arranged in a way that prevents movement relative to the sensor element (1; 1'), or -The magnet device arranged on the component (2) with respect to the first direction (x) is located next to it, wherein The supporting magnets (1.6, 2.11) are configured such that the domain wall conductors (1.1; 1.1') can be initialized by the magnetic field of the supporting magnets (1.6, 2.11) superimposed on the magnetic field of the conductive layer (1.7).

12. The memory system according to claim 11, wherein, The sensor element (1; 1') is arranged between the magnet device (1.3; 1.3'') and the supporting magnet (1.6).

13. The memory system according to claim 11 or 12, wherein, The supporting magnets (1.6, 2.11) are arranged such that the connecting line between the north pole and the south pole of the supporting magnet is oriented in a second direction (y), wherein the second direction has a component orthogonal to the first direction (x).

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