# US 8,786,987 B2 · Biased two dimensional magnetic sensor > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,786,987 B2 - Document ID: US8786987B2 - Status: Granted - Kind: B2 - Application number: 13/458,745 - Filed: 2012-04-27 - Published: 2013-10-31 - Granted: 2014-07-22 - Earliest claimed: 2012-04-27 - Assignees: Seagate Technology LLC - Applicants: Harry Sam Edelman; Thomas Roy Boonstra - Inventors: Harry Sam Edelman; Thomas Roy Boonstra - Web page: https://patentgrep.com/patent/US8786987B2 ## CPC - G11B 5/4976: {Disposition of heads, e.g. matrix arrangement} - G11B 5/29: Structure or manufacture of unitary devices formed of plural heads for more than one track {(G11B5/33, G11B5/49 and subgroups take precedence; in thin film structure G11B5/31)} - G11B 5/3932: {Magnetic biasing films} - G11B 5/3948: {the sensitive elements being active read-out elements} - G11B 5/397: {with a plurality of independent magnetoresistive active read-out elements for respectively transducing from selected components} - G11B 5/4886: {relative to rotating disc} - G11B 5/3909: {Arrangements using a magnetic tunnel junction} - G11B 5/3912: {Arrangements in which the active read-out elements are transducing in association with active magnetic shields, e.g. magnetically coupled shields (G11B5/3916 takes precedence)} - 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) ## Abstract Apparatus for two dimensional reading. In accordance with some embodiments, a magnetic read element has a bias magnet disposed between a plurality of read sensors. The bias magnet may be configured to concurrently bias each read sensor to a predetermined magnetization. ## Claims ### Claim 1 An apparatus comprising: a bias magnet disposed between a plurality of read sensors, the bias magnet configured to concurrently bias each read sensor to a predetermined magnetization, wherein each read sensor comprises a trilayer stack characterized as comprising first and second magnetically free layers separated by a non-magnetic spacer and biased to the predetermined magnetization only by the bias magnet. ### Claim 2 (depends on 1) The apparatus of claim 1, wherein the read sensors and bias magnet share top and bottom magnetic shields. ### Claim 3 (depends on 2) The apparatus of claim 2, wherein the top shield is split into sub-shields by an isolation trench proximal the bias magnet. ### Claim 4 (depends on 2) The apparatus of claim 2, wherein at least the top shield is a nano-shield. ### Claim 5 (depends on 4) The apparatus of claim 4, wherein each nano-shield is circularly shaped. ### Claim 6 (depends on 4) The apparatus of claim 4, wherein the nano-shield has a circular aperture distal to an air bearing surface of the trilayer read sensors. ### Claim 7 (depends on 1) The apparatus of claim 1, wherein each trilayer stack is further characterized by a lack of a reference layer pinned to a fixed magnetic orientation. ### Claim 8 (depends on 1) The apparatus of claim 1, wherein the plurality of read sensors is electrically accessed with only three electrical leads. ### Claim 9 (depends on 1) The apparatus of claim 1, wherein each read sensor and the bias magnet are positioned on an air bearing surface. ### Claim 10 A magnetic read element comprising: a plurality of read sensors formed on an air bearing surface (ABS) by an isolation trench dissecting a plurality of layers; and a bias magnet disposed between the plurality of read sensors, distal the ABS, the bias magnet configured to concurrently bias each read sensor to a predetermined magnetization, wherein the isolation trench dissects a top magnetic shield that extends adjacent each of the plurality of read sensors. ### Claim 11 (depends on 10) The magnetic read element of claim 10, wherein the isolation trench dissects less than all the layers of the plurality of read sensors. ### Claim 12 (depends on 10) The magnetic read element of claim 10, wherein the plurality of read sensors are characterized as trilayer read sensors formed from a single continuous read sensor. ### Claim 13 (depends on 10) The magnetic read element of claim 10, wherein each of the plurality of read sensors is positioned to simultaneously access user data from adjacent data tracks on an adjacent data storage media. ### Claim 14 (depends on 13) The magnetic read element of claim 13, wherein the simultaneous access to user data is used in two-dimensional data reading. ### Claim 15 A transducing head comprising: first and second read sensors; a bias magnet positioned on an air bearing surface (ABS) and configured to concurrently bias the first and second read sensors to a predetermined magnetization; and a permanent magnet positioned distal the ABS and between the first and second read sensors. ### Claim 16 (depends on 15) The transducing head of claim 15, wherein the permanent magnet is characterized as a first permanent magnet, and wherein the transducing head further comprises a second permanent magnet is positioned on the ABS adjacent the second read sensor and distal the first read sensor, the bias magnet and the first permanent magnet. ### Claim 17 An apparatus comprising: first and second read sensors; a bias magnet configured to concurrently bias each of the first and second read sensors to a predetermined magnetization; and top and bottom magnetic shields respectively adjacent the first and second read sensors and the bias magnet, wherein the top and bottom magnetic shields each continuously extend from the first read sensor to the second read sensor, and wherein the top shield is split into sub-shields by an isolation trench proximal the bias magnet. ### Claim 18 (depends on 17) The apparatus of claim 17, wherein at least a selected one of the top or bottom shields is a nano-shield. ### Claim 19 (depends on 17) The apparatus of claim 17, wherein at least a selected one of the top or bottom shields is a synthetic antiferromagnetic lamination. ### Claim 20 (depends on 17) The apparatus of claim 17, wherein the bias magnet is positioned on an air bearing surface (ABS), and the apparatus further comprises a permanent magnet positioned distal the ABS and between the first and second trilayer read sensors.