# US 2012/0074510 A1 · Magnetic sensor and magnetic head > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2012/0074510 A1 - Document ID: US20120074510A1 - Status: Published application - Kind: A1 - Application number: 13/227,135 - Filed: 2011-09-07 - Published: 2012-03-29 - Earliest claimed: 2010-09-24 - Assignees: TDK Corporation - Inventors: Tomoyuki SASAKI; Tohru OIKAWA - Web page: https://patentgrep.com/patent/US20120074510A1 ## CPC - G01R 33/093: {using multilayer structures, e.g. giant magnetoresistance sensors (thin magnetic films H01F10/00)} - G11B 5/332: {using thin films (G11B5/372, G11B5/3903 take precedence)} - H10N 50/10: Magnetoresistive devices - H10N 50/85: Materials of the active region - G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12) - G11B: INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER (recording measured values in a way that does not require playback through a transducer G01D9/00; recording or playback apparatus using mechanically marked tape, e.g. punched paper tape, or using unit records, e.g. punched or magnetically marked cards G06K; transferring data from one type of record carrier to another G06K1/18; circuits for coupling output of reproducer to radio receiver H04B1/20; gramophone pick-ups or like acoustic electromechanical transducers or circuits therefor H04R) - H10N: ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR ## Abstract A magnetic sensor 1 comprises a main channel layer 7a having first, second, and third regions 71, 72, 73 and extending in a first direction; a first ferromagnetic layer 12A mounted on the first region 71; a second ferromagnetic layer 12B mounted on the second region 72; a projection channel layer 7b projecting in a direction perpendicular to a thickness direction of the main channel layer 7a from a side face of the third region 73 between the first and second regions 71, 72 in the main channel layer 7a; and a magnetic shield S covering both sides in the thickness direction of the projection channel layer 7b and both sides in the first direction of the projection channel layer 7b and exposing an end face 7c in the projecting direction of the projection channel layer 7b. ## Claims ### Claim 1 A magnetic sensor comprising: a main channel layer having first, second, and third regions and extending in a first direction; a first ferromagnetic layer mounted on the first region; a second ferromagnetic layer mounted on the second region; a projection channel layer projecting in a direction perpendicular to a thickness direction of the main channel layer from a side face of the third region between the first and second regions in the main channel layer; and a magnetic shield covering both sides in the thickness direction of the projection channel layer and both sides in the first direction of the projection channel layer and exposing an end face in the projecting direction of the projection channel layer. ### Claim 2 (depends on 1) A magnetic sensor according to claim 1, wherein the first and second ferromagnetic layers have a direction of magnetization perpendicular to the projecting direction of the projection channel layer. ### Claim 3 (depends on 1) A magnetic sensor according to claim 1, wherein the first and second ferromagnetic layers have the same direction of magnetization. ### Claim 4 (depends on 1) A magnetic sensor according to claim 1, wherein the first and second ferromagnetic layers have a direction of magnetization in the first direction. ### Claim 5 (depends on 1) A magnetic sensor according to claim 1, wherein the first and second ferromagnetic layers have a direction of magnetization identical to a direction of mounting the first and second ferromagnetic layers with respect to the main channel layer. ### Claim 6 (depends on 1) A magnetic sensor according to claim 1, wherein the end face in the projecting direction of the projection channel has one of rectangular, triangular, trapezoidal, and circular forms. ### Claim 7 (depends on 1) A magnetic sensor according to claim 1, wherein a side face of the main channel layer on a side opposite from the projection channel layer is depressed. ### Claim 8 (depends on 3) A magnetic sensor according to claim 3, wherein the direction of magnetization of the first and second ferromagnetic layers is pinned by antiferromagnetic layers arranged on the first and second ferromagnetic layers, respectively. ### Claim 9 (depends on 1) A magnetic sensor according to claim 1, wherein, between the first and second ferromagnetic layers, surfaces of the main and projection channel layers are covered with an insulating layer. ### Claim 10 (depends on 1) A magnetic sensor according to claim 1, wherein, between the first and second ferromagnetic layers, the main and projection channel layers are electrically insulated from the magnetic shield. ### Claim 11 (depends on 1) A magnetic sensor according to claim 1, further comprising a permanent magnet for supplying a magnetic field to the main channel layer through the end face of the projection channel layer. ### Claim 12 (depends on 1) A magnetic sensor according to claim 1, wherein the first and second ferromagnetic layers are made of a metal selected from the group consisting of Cr, Mn, Co, Fe, and Ni; an alloy containing at least one element selected from the group; or a compound containing at least one element selected from the group and at least one element selected from the group consisting of B, C, N, Si, and Ge. ### Claim 13 (depends on 1) A magnetic sensor according to claim 1, wherein the main and projection channel layers are made of a semiconductor containing at least one of Si, Ge, GaAs, C, and ZnO. ### Claim 14 (depends on 1) A magnetic sensor according to claim 1, wherein a barrier is formed between at least one of the first and second ferromagnetic layers and the main channel layer. ### Claim 15 (depends on 14) A magnetic sensor according to claim 14, wherein the barrier is a tunnel barrier made of an insulating film. ### Claim 16 (depends on 14) A magnetic sensor according to claim 14, wherein the barrier is a Schottky barrier. ### Claim 17 (depends on 1) A magnetic head comprising: a reading head unit constituted by the magnetic sensor according to claim 1; and a recording head unit for writing disposed on the reading head unit.