# US 10,121,501 B2 · Free layer magnetic reader that may have a reduced shield-to-shield spacing > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,121,501 B2 - Document ID: US10121501B2 - Status: Granted - Kind: B2 - Application number: 15/597,342 - Filed: 2017-05-17 - Published: 2017-08-31 - Granted: 2018-11-06 - Earliest claimed: 2015-09-23 - Assignees: Western Digital (Fremont), LLC - Applicants: Western Digital (Fremont), LLC - Inventors: Gerardo A. Bertero; Shaoping Li; Qunwen Leng; Yuankai Zheng; Rongfu Xiao; Ming Mao; Shihai He; Miaoyin Wang - Web page: https://patentgrep.com/patent/US10121501B2 ## CPC - 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 5/115: Shielding devices arranged between heads or windings ({G11B5/265} , G11B5/29 take precedence) - G11B 5/3906: {Details related to the use of magnetic thin film layers or to their effects} - G11B 5/3909: {Arrangements using a magnetic tunnel junction} - G11B 5/3932: {Magnetic biasing films} - G11B 5/398: {Specially shaped layers} - G11B 2005/3996: {large or giant magnetoresistive effects [GMR], e.g. as generated in spin-valve [SV] devices} - 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 A magnetic read apparatus includes a read sensor, a shield structure and a side magnetic bias structure. The read sensor includes a free layer having a side and a nonmagnetic spacer layer. The shield structure includes a shield pinning structure and a shield reference structure. The nonmagnetic spacer layer is between the shield reference structure and the free layer. The shield reference structure is between the shield pinning structure and the nonmagnetic spacer layer. The shield pinning structure includes a pinned magnetic moment in a first direction. The shield reference structure includes a shield reference structure magnetic moment weakly coupled with the pinned magnetic moment. The side magnetic bias structure is adjacent to the side of the free layer. ## Claims ### Claim 1 A magnetic read apparatus comprising: a read sensor; a shield structure comprising: a shield pinning structure; a shield reference structure; and a nonmagnetic coupling layer between the shield pinning structure and the shield reference structure; and a top shield structure comprising: a first ferromagnetic layer; a second ferromagnetic layer; a nonmagnetic layer between the first ferromagnetic layer and the second ferromagnetic layer; an antiferromagnetic layer; and a top shield, wherein the antiferromagnetic layer is between the top shield and the second ferromagnetic layer, wherein the read sensor is between the top shield structure and the shield structure. ### Claim 2 (depends on 1) The magnetic read apparatus of claim 1, wherein the shield pinning structure comprises a pinning layer and a magnetic layer, wherein the magnetic layer abuts the nonmagnetic coupling layer. ### Claim 3 (depends on 1) The magnetic read apparatus of claim 1, wherein the shield reference structure comprises a first magnetic layer, a second magnetic layer, and a nonmagnetic layer between the first magnetic layer and the second magnetic layer, wherein the first magnetic layer abuts a nonmagnetic spacer layer of the read sensor and the second magnetic layer abuts the nonmagnetic coupling layer. ### Claim 4 (depends on 1) The magnetic read apparatus of claim 1, wherein the shield structure further comprises a bottom shield located under and abutting the shield pinning structure. ### Claim 5 (depends on 1) The magnetic read apparatus of claim 1, further comprising a side magnetic bias structure located on either side of the read sensor adjacent to a free layer of the read sensor. ### Claim 6 (depends on 5) The magnetic read apparatus of claim 5, wherein the side magnetic bias structure is separated from the read sensor on the either side by an insulating layer. ### Claim 7 (depends on 1) The magnetic read apparatus of claim 1, further comprising a rear bias structure, wherein the read sensor is between an air bearing surface of the magnetic read apparatus and the rear bias structure, and wherein the read sensor is separated from the rear bias structure by a nonmagnetic insulator layer. ### Claim 8 (depends on 7) The magnetic read apparatus of claim 7, wherein the rear bias structure has a width in a cross-track direction that is greater than a track width of the read sensor in the cross-track direction, wherein the cross-track direction extends along a plane that is parallel to the air bearing surface. ### Claim 9 (depends on 1) The magnetic read apparatus of claim 1, wherein the shield pinning structure is wider than the shield reference structure in a cross-track direction that is parallel to an air bearing surface. ### Claim 10 A magnetic read apparatus comprising: a read sensor comprising a free layer and a nonmagnetic spacer layer; a top shield structure comprising: a first ferromagnetic layer; a second ferromagnetic layer; a nonmagnetic layer between the first ferromagnetic layer and the second ferromagnetic layer; an antiferromagnetic layer; and a top shield, wherein the antiferromagnetic layer is between the top shield and the second ferromagnetic layer; and a shield structure, wherein the read sensor is between the top shield structure and the shield structure. ### Claim 11 (depends on 10) The magnetic read apparatus of claim 10, wherein the read sensor further comprises a capping layer between the free layer and the first ferromagnetic layer. ### Claim 12 (depends on 10) The magnetic read apparatus of claim 10, further comprising: a bottom shield abutting a pinning layer of the shield structure; and a side magnetic bias structure located on either side of the read sensor. ### Claim 13 (depends on 10) The magnetic read apparatus of claim 10, wherein the shield structure comprises a shield pinning structure and a shield reference structure separated by a nonmagnetic coupling layer. ### Claim 14 (depends on 13) The magnetic read apparatus of claim 13, wherein the shield pinning structure comprises a pinning layer and a magnetic layer between the pinning layer and the nonmagnetic coupling layer. ### Claim 15 (depends on 14) The magnetic read apparatus of claim 14, wherein the shield reference structure comprises a first magnetic layer, a second magnetic layer and a nonmagnetic layer between the first magnetic layer and the second magnetic layer. ### Claim 16 (depends on 13) The magnetic read apparatus of claim 13, wherein the shield pinning structure is wider than the shield reference structure in a cross-track direction that is parallel to an air bearing surface. ### Claim 17 A magnetic read apparatus comprising: a read sensor; a shield structure; a top shield structure comprising: a first ferromagnetic layer; a second ferromagnetic layer; a nonmagnetic layer between the first ferromagnetic layer and the second ferromagnetic layer; an antiferromagnetic layer; and a top shield, wherein the antiferromagnetic layer is between the top shield and the second ferromagnetic layer; and a bottom shield, wherein the read sensor is between the top shield structure and the shield structure; and wherein the shield structure is between the read sensor and the bottom shield. ### Claim 18 (depends on 17) The magnetic read apparatus of claim 17, further comprising a capping layer between the read sensor and the first ferromagnetic layer of the top shield structure. ### Claim 19 (depends on 17) The magnetic read apparatus of claim 17, wherein the shield structure comprises a shield pinning structure and a shield reference structure, and wherein the shield pinning structure is wider than the shield reference structure in a cross-track direction that is parallel to an air bearing surface. ### Claim 20 (depends on 19) The magnetic read apparatus of claim 19, wherein the bottom shield is wider than the shield pinning structure in the cross-track direction.