# US 8,542,461 B2 · Writer shields with modified shapes for reduced flux shunting > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,542,461 B2 - Document ID: US8542461B2 - Status: Granted - Kind: B2 - Application number: 12/806,803 - Filed: 2010-08-20 - Published: 2012-02-23 - Granted: 2013-09-24 - Earliest claimed: 2010-08-20 - Assignees: Headway Technologies, Inc. - Applicants: Zhigang Bai; Moris Dovek; Yan Wu - Inventors: Zhigang Bai; Moris Dovek; Yan Wu - Web page: https://patentgrep.com/patent/US8542461B2 ## CPC - G11B 5/3163: {Fabrication methods or processes specially adapted for a particular head structure, e.g. using base layers for electroplating, using functional layers for masking, using energy or particle beams for shaping the structure or modifying the properties of the basic layers} - G11B 5/1278: {specially adapted for magnetisations perpendicular to the surface of the record carrier} - G11B 5/3116: {Shaping of layers, poles or gaps for improving the form of the electrical signal transduced, e.g. for shielding, contour effect, equalizing, side flux fringing, cross talk reduction between heads or between heads and information tracks (G11B5/3113, G11B5/245 take precedence)} - G11B 5/312: {for reducing flux leakage between the electrical coil layers and the magnetic cores or poles or between the magnetic cores or poles} - G11B 5/3146: {magnetic layers} - 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 perpendicular magnetic recording (PMR) head is fabricated with a configuration of leading edge shields and trailing edge shields that reduce the leakage of flux between the main pole and the shields. The reduction of leakage is achieved by eliminating the sharp 90° corner between the backside surfaces of the shields and the surfaces adjacent to the main pole. In one embodiment the corner is replaced by two successive acute angles, in another embodiment it is replaced by a rounded surface. In a final embodiment, leakage between the pole and trailing edge shield is achieved by shortening the length of the write gap by forming the shield with a double taper. ## Claims ### Claim 1 PMR head comprising: a main pole having a first portion of a trailing edge surface upwardly tapered at an angle α relative to a perpendicular to an ABS and extending away from said ABS for a perpendicular distance tWGd and a second portion having no taper and a uniform width thereafter; a trailing edge shield having an ABS, a back surface parallel to said ABS and separated from said ABS by a distance TH and a doubly angled leading edge surface joining said ABS and said back surface, wherein a first portion of said leading edge surface is a plane that contacts said ABS and makes an angle β with a perpendicular to said ABS and extends a perpendicular distance eTH from said ABS and wherein a second portion of said of said leading edge surface is a plane that joins said first portion to said back surface and makes an angle γ with a perpendicular to said ABS; wherein the separation between said first portion of said main pole and said first portion of said leading edge surface of said trailing edge shield forms a writer gap portion of substantially uniform width and wherein a separation between said main pole and said second portion of said leading edge surface of said trailing edge shield increases with distance perpendicularly away from said ABS. ### Claim 2 (depends on 1) The PMR head of claim 1 wherein said pole and shield are preferably formed of the magnetic materials FeNi, CoFe, CoNiFe, CoFeN or CoFePd and wherein said writer gap is filled any of the non-magnetic dielectric materials Al2O3, SiO2 , TiO2, or the metals Ru, Ta, NiCr, or NiNb. ### Claim 3 (depends on 1) The PMR head of claim 1 wherein the angle α is between approximately 5° and 45°. ### Claim 4 (depends on 1) The PMR head of claim 1 wherein the angle β is between approximately 5° and 45°. ### Claim 5 (depends on 1) The PMR head of claim 1 wherein the angle γ is larger than angle β and is between approximately 30° and 80°. ### Claim 6 (depends on 1) The PMR head of claim 1 wherein eTH is smaller than or equal to TH. ### Claim 7 (depends on 1) The PMR head of claim 1 wherein tWGd is between approximately 30 nm and 400 nm. ### Claim 8 (depends on 1) The PMR head of claim 1 wherein said main pole has a thickness between approximately 0.2 microns and 0.6 microns. ### Claim 9 (depends on 1) The PMR head of claim 1 also including a leading edge shield and side shields. ### Claim 10 A PMR head comprising: a main pole having a tapered portion on a trailing edge side in a direction away from an ABS and an untapered portion having a uniform width thereafter; a trailing edge shield having an ABS, a back surface parallel to said ABS and a leading edge surface joining said ABS and said back surface, wherein a separation between said leading edge surface and said tapered portion of said main pole forms a writer gap; wherein said leading edge surface joins said back surface at a tapered corner formed by two successive obtuse angles α having vertices separated vertically by a distance h; whereby a single 90° corner between said leading edge surface and said back surface is, thereby, eliminated and wherein a separation between said main pole and said tapered corner increases with a distance perpendicularly away from said ABS. ### Claim 11 (depends on 10) The PMR head of claim 10 wherein said angles α range in value between approximately 120° and 170° and said height h ranges in value between approximately 0.05 and 0.3 microns. ### Claim 12 (depends on 10) The PMR head of claim 10 wherein said pole and shield are preferably formed of the magnetic materials FeNi, CoFe, CoNiFe, CoFeN or CoFePd and wherein said writer gap is filled any of the non-magnetic dielectric materials Al2O3, SiO2, TiO2, or the metals Ru, Ta, NiCr, or NiNb. ### Claim 13 (depends on 10) The PMR head of claim 10 wherein said main pole has a thickness between approximately 0.2 microns and 0.6 microns. ### Claim 14 (depends on 10) The PMR head of claim 10 also including a leading edge shield and side shields. ### Claim 15 A PMR head comprising: a main pole having a tapered portion on a trailing edge side in a direction away from an ABS and having a uniform width thereafter; a trailing edge shield having an ABS, a back surface parallel to said ABS and a leading edge surface joining said ABS and said back surface, wherein a separation between said leading edge surface and said tapered portion of said main pole forms a write gap; wherein said leading edge surface joins said back surface at a rounded corner; whereby a single 90° corner between said leading edge surface and said back surface is eliminated and wherein the separation between said leading edge surface of said trailing edge shield increases at said rounded corner with a distance perpendicularly away from said ABS. ### Claim 16 (depends on 15) The PMR head of claim 15 wherein said pole and shield are preferably formed of the magnetic materials FeNi, CoFe, CoNiFe, CoFeN or CoFePd and wherein said writer gap is filled any of the non-magnetic dielectric materials Al2O3, SiO2, TiO2, or the metals Ru, Ta, NiCr, or NiNb. ### Claim 17 (depends on 15) The PMR head of claim 15 wherein said main pole has a thickness between approximately 0.2 microns and 0.6 microns. ### Claim 18 (depends on 15) The PMR head of claim 15 also including a leading edge shield and side shields. ### Claim 19 (depends on 15) The PMR head of claim 15 wherein said rounded corner has a radius of curvature of between approximately 50 and 300 nm. ### Claim 20 A PMR head comprising: a main pole tapered on a trailing edge side for a distance tWGd in a direction away from an ABS and having a uniform width thereafter; a leading edge shield having an ABS, a back surface parallel to said ABS and a trailing edge surface joining said ABS and said back surface, wherein a separation between said trailing edge surface and said main pole forms a leading edge gap; wherein said trailing edge surface joins said back surface at a tapered corner formed by two successive obtuse angles α′ having vertices separated by a vertical distance h′; whereby a single 90° corner between said leading edge surface and said back surface of said leading edge shield is eliminated and wherein a separation between said main pole and said tapered corner of said trailing edge surface of said leading edge shield increases with a distance perpendicularly away from said ABS. ### Claim 21 (depends on 20) The PMR head of claim 20 wherein said angles α′ range in value between approximately 120° and 170° and said height h′ ranges in value between approximately 0.05 and 0.3 microns. ### Claim 22 (depends on 20) The PMR head of claim 20 wherein said pole and shield are preferably formed of the magnetic materials FeNi, CoFe, CoNiFe, CoFeN or CoFePd and wherein said leading edge gap is filled any of the non-magnetic dielectric materials Al2O3, SiO2, TiO2, or the metals Ru, Ta, NiCr, or NiNb. ### Claim 23 (depends on 20) The PMR head of claim 20 wherein said main pole has a thickness between approximately 0.2 microns and 0.6 microns. ### Claim 24 (depends on 20) The PMR head of claim 20 also including a trailing edge shield and side shields. ### Claim 25 A PMR head comprising: a main pole tapered for a distance tWGd on a trailing edge side in a direction away from an ABS and having a uniform width thereafter; a leading edge shield having an ABS, a back surface parallel to said ABS and a trailing edge surface joining said ABS and said back surface, wherein a separation between said trailing edge surface and said main pole forms a leading edge gap; wherein said trailing edge surface joins said back surface at a rounded corner; whereby a single 90° corner between said leading edge surface and said back surface of said leading edge shield is eliminated and wherein a separation between said main pole and said rounded corner of said trailing edge surface of said leading edge shield increases with a distance perpendicularly away from said ABS. ### Claim 26 (depends on 25) The PMR head of claim 25 wherein said pole and shield are preferably formed of the magnetic materials FeNi, CoFe, CoNiFe, CoFeN or CoFePd and wherein said leading edge gap is filled any of the non-magnetic dielectric materials Al2O3, SiO2, TiO2, or the metals Ru, Ta, NiCr, or NiNb. ### Claim 27 (depends on 25) The PMR head of claim 25 wherein said main pole has a thickness between approximately 0.2 microns and 0.6 microns. ### Claim 28 (depends on 25) The PMR head of claim 25 wherein said rounded corner has a radius of curvature of between approximately 50 and 300 nm. ### Claim 29 (depends on 25) The PMR head of claim 25 also including a trailing edge shield and side shields.