# US 8,786,280 B2 · Magneto-resistance effect element and sensor > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,786,280 B2 - Document ID: US8786280B2 - Status: Granted - Kind: B2 - Application number: 12/845,992 - Filed: 2010-07-29 - Published: 2011-02-03 - Granted: 2014-07-22 - Earliest claimed: 2009-07-31 - Assignees: TDK Corporation - Applicants: Hiroshi Yamazaki; Hiraku Hirabayashi; Naoki Ohta - Inventors: Hiroshi Yamazaki; Hiraku Hirabayashi; Naoki Ohta - Web page: https://patentgrep.com/patent/US8786280B2 ## CPC - G01R 33/091: {Constructional adaptation of the sensor to specific applications} - G01R 33/0005: {Geometrical arrangement of magnetic sensor elements; Apparatus combining different magnetic sensor types (G01R33/0206 takes precedence)} - G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12) ## Abstract A magneto-resistance effect element for a sensor to sense a variation in externally applied magnetism includes a pinned layer having a fixed magnetization direction, a free layer having a magnetization direction which varies in response to an external magnetic field, and an intermediate layer provided between the pinned layer and the free layer. The pinned layer has a planar shape which is long in the fixed magnetization direction and which is short in a direction orthogonal to the fixed magnetization direction. Moreover, the pinned layer preferably has a planar shape in which the pinned layer is divided into a plurality of sections. ## Claims ### Claim 1 A magneto-resistance effect element, comprising: a stack of layers comprising a pinned layer, a free layer, and an intermediate layer between the pinned layer and the free layer; the pinned layer having: a length direction, a width direction, and a thickness direction, the thickness direction being in a direction of stacking of the stack of layers, the length and width directions being perpendicular to each other and defining a plane that is orthogonal to the thickness direction; a fixed magnetization direction that is orthogonal to the thickness direction of the pinned layer and parallel to the length direction of the pinned layer; and a planar shape in the plane defined by the length and width directions of the pinned layer, the planar shape being longer in the length direction than in the width direction of the pinned layer; and the free layer having: a length direction, a width direction, and a thickness direction, the thickness direction being in a direction of stacking of the stack of layers, the length and width directions being a perpendicular to each other and defining a plane that is orthogonal to the thickness direction; a circular planar shape or an elliptical planar shape within the plane defined by the length and width directions of the free layer; and a magnetization direction which varies in response to an external magnetic field; wherein: the pinned layer is divided into a plurality of sections within the plane defined by the length and width directions of the pinned layer, each section being longer in the length direction than in the width direction of the pinned layer. ### Claim 2 (depends on 1) The magneto-resistance effect element according to claim 1, wherein the planar shape of the pinned layer has a length in the length direction of the pinned layer that is at least three times as large as a length in the width direction of the pinned layer. ### Claim 3 (depends on 1) The magneto-resistance effect element according to claim 1, wherein the free layer has a circular planar shape. ### Claim 4 (depends on 1) The magneto-resistance effect element according to claim 1, wherein a total area of the free layer in the plane defined by the length and width directions of the free layer is larger than an area of a portion of the pinned layer in the plane defined by the length and width directions of the pinned layer that overlaps the free layer as seen in a plan view looking along the direction of stacking of the stack of layers. ### Claim 5 (depends on 4) The magneto-resistance effect element according to claim 4, wherein a total area of the free layer in the plane defined by the length and width directions of the free layer is larger than an area of the pinned layer in the plane defined by the length and width directions of the pinned layer. ### Claim 6 (depends on 1) The magneto-resistance effect element according to claim 1, wherein the intermediate layer is an insulating layer or a nonmagnetic layer or an insulating and nonmagnetic layer. ### Claim 7 (depends on 1) A sensor comprising: a sensing circuit comprising a Wheatstone bridge having a plurality of the magneto-resistance effect elements according to claim 1 connected to each other, and a magnet provided at a position opposite to the sensing circuit, wherein the sensor is configured to sense a variation in a positional relationship between the magnet and the sensing circuit by sensing a variation in a resistance value of each of the magneto-resistance effect elements resulting from a variation in a magnetic force exerted by the magnet on the free layer of each of the magneto-resistance effect elements. ### Claim 8 (depends on 7) The sensor according to claim 7, wherein the magnet is mounted on a sense target member and the sensing circuit is fixed at a position opposite to the magnet, the sensor being further configured to sense a variation in the angle of the sense target member by sensing a variation in the resistance value of each of the magneto-resistance effect elements. ### Claim 9 A magneto-resistance effect element, comprising: a stack of layers comprising a pinned layer, a free layer, and an intermediate layer between the pinned layer and the free layer; the pinned layer having: a length direction, a width direction, and a thickness direction, the thickness direction being in a direction of stacking of the stack of layers, the length and width directions being perpendicular to each other and defining a plane that is orthogonal to the thickness direction; a fixed magnetization direction that is orthogonal to the thickness direction of the pinned layer and parallel to the length direction of the pinned layer; and a planar shape in the plane defined by the length and width directions of the pinned layer the planar shape being longer in the length direction than in the width direction of the pinned layer; and the free layer having: a length direction, a width direction, and a thickness direction, the thickness direction being in a direction of stacking of the stack of layers, the length and width directions being perpendicular to each other and defining a plane that is orthogonal to the thickness direction; a circular planar shape or an elliptical planar shape within the plane defined by the length and width directions of the free layer; and a magnetization direction which varies in response to an external magnetic field; wherein: the pinned layer is divided into a plurality of sections within the plane defined by the length and width directions of the pinned layer, each section being longer in the length direction than in the width direction of the pinned layer; an area between the sections of the pinned layer is filled with an insulating layer; and a total area of the free layer in the plane defined by the length and width directions of the free layer is larger than an area of the pinned layer in the plane defined by the length and width directions of the pinned layer. ### Claim 10 (depends on 9) The magneto-resistance effect element according to claim 9, wherein the planar shape of the pinned layer has a length in the length direction of the pinned layer that is at least three times as large as a length in the width direction of the pinned layer. ### Claim 11 (depends on 9) The magneto-resistance effect element according to claim 9, wherein the free layer has a circular planar shape. ### Claim 12 (depends on 9) The magneto-resistance effect element according to claim 9, wherein a total area of the free layer in the plane defined by the length and width directions of the free layer is larger than an area of a portion of the pinned layer in the plane defined by the length and width directions of the pinned layer that overlaps the free layer as seen in a plan view looking along the direction of stacking of the stack of layers. ### Claim 13 (depends on 9) The magneto-resistance effect element according to claim 9, wherein the intermediate layer is an insulating layer or a nonmagnetic layer or an insulating and nonmagnetic layer. ### Claim 14 (depends on 9) A sensor comprising: a sensing circuit comprising a Wheatstone bridge having a plurality of the magneto-resistance effect elements according to claim 9 connected to each other, and a magnet provided at a position opposite to the sensing circuit, wherein the sensor is configured to sense a variation in a positional relationship between the magnet and the sensing circuit by sensing a variation in a resistance value of each of the magneto-resistance effect elements resulting from a variation in a magnetic force exerted by the magnet on the free layer of each of the magneto-resistance effect elements. ### Claim 15 (depends on 14) The sensor according to claim 14, wherein the magnet is mounted on a sense target member and the sensing circuit is fixed at a position opposite to the magnet, the sensor being further configured to sense a variation in the angle of the sense target member by sensing a variation in the resistance value of each of the magneto-resistance effect elements.