# US 9,040,180 B2 · Perpendicular magnetic recording disk with multiple magnetic layers and intermediate dual nucleation films for control of grain size > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,040,180 B2 - Document ID: US9040180B2 - Status: Granted - Kind: B2 - Application number: 13/156,272 - Filed: 2011-06-08 - Published: 2012-12-13 - Granted: 2015-05-26 - Earliest claimed: 2011-06-08 - Assignees: HGST Netherlands B.V. - Applicants: Ernesto E. Marinero; Dieter K. Weller; Brian R. York - Inventors: Ernesto E. Marinero; Dieter K. Weller; Brian R. York - Web page: https://patentgrep.com/patent/US9040180B2 ## CPC - G11B 5/676: {having magnetic layers separated by a nonmagnetic layer, e.g. antiferromagnetic layer, Cu layer or coupling layer} - G11B 5/672: {having different compositions in a plurality of magnetic layers, e.g. layer compositions having differing elemental components or differing proportions of elements} - G11B 5/7369: {Two or more non-magnetic underlayers, e.g. seed layers or barrier layers} - G11B 5/82: Disk carriers - 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 disk has a graded-anisotropy recording layer (RL) formed of at least two ferromagnetically exchange coupled CoPtCr-oxide magnetic layers (MAG1 and MAG2) with two nucleation films (NF1 and NF2) between the magnetic layers. NF1 is a metal film, preferably Ru or a Ru-based alloy like RuCr, sputter deposited on MAG1 at low pressure to a thickness between about 0.1-1.5 nm. NF2 is a metal oxide film, preferably an oxide of Ta, sputter deposited on NF1 at high pressure to a thickness between about 0.2-1.0 nm. MAG2 is sputter deposited over NF2. NF1 and NF2 provide a significant reduction in average grain size in the RL from a graded-anisotropy RL without nucleation films between MAG1 and MAG2, while also assuring that MAG1 and MAG2 are strongly exchange coupled. ## Claims ### Claim 1 A perpendicular magnetic recording disk comprising: a substrate; an underlayer of magnetically permeable material on the substrate; a nonmagnetic intermediate layer (IL) on the underlayer and comprising a material selected from Ru and a Ru alloy; a perpendicular magnetic recording layer comprising a first magnetic layer (MAG1 ) comprising a granular ferromagnetic alloy comprising Co, Pt and Cr and one or more oxides of one or more of Si, Ta, Ti, Nb and B on the IL; a first nucleation film (NF1 ) consisting of a material selected from Ru and a Ru-based alloy on and in contact with MAG1 and having a thickness greater than or equal to 0.1 nm and less than or equal to 1.5 nm; a second nucleation film (NF2 ) consisting of an oxide of Ta on and in contact with NF1 and having a thickness greater than or equal to 0.2 nm and less than or equal to 1.0 nm; and a second magnetic layer (MAG2 ) ferromagnetically exchange coupled to MAG1 across NF1 and NF2, MAG2 being formed of a granular ferromagnetic alloy comprising Co, Pt and Cr and one or more oxides of one or more of Si, Ta, Ti, Nb and B on and in contact with NF2, wherein MAG2 has an anisotropy field greater than the anisotropy field of MAG1. ### Claim 2 (depends on 1) The disk of claim 1 wherein NF2 is a discontinuous film of oxide clusters on and in contact with NF1 , wherein MAG2 is in contact with the oxide clusters of NF2. ### Claim 3 (depends on 1) The disk of claim 1 wherein NF1 is a conformal film of NF1 material on and in contact with MAG1. ### Claim 4 (depends on 1) the disk of claim 1 wherein NF1 is a discontinuous film Of NF1 material on and in contact with MAG1. ### Claim 5 (depends on 1) The disk of claim 1 wherein NF1 has a thickness equal to or greater than 0.5 nm and less than or equal to 1.2 nm. ### Claim 6 (depends on 1) The disk of claim 1 wherein NF2 has a thickness equal to or greater than 0.4 nm and less than or equal to 0.8 nm. ### Claim 7 (depends on 1) The disk of claim 1 wherein NF1 consists of a RuCr alloy. ### Claim 8 (depends on 1) The disk of claim 1 wherein NF1 consists of RuxCo(100-x), where x is in atomic percent and is greater than or equal to 30 and less than or equal to 70. ### Claim 9 (depends on 1) The disk of claim 1 wherein the underlayer of magnetically permeable material is formed of a material selected from the group consisting of alloys of CoFe, CoNiFe, NiFe, FeCoB, CoCuFe, FeAlSi, FeTaN, FeN, FeTaC, CoTaZr and CoZrNb. ### Claim 10 (depends on 1) The disk of claim 1 wherein the underlayer of magnetically permeable material is a lamination of multiple magnetically permeable films separated by nonmagnetic films. ### Claim 11 (depends on 10) The disk of claim 10 wherein the nonmagnetic films in the lamination provide antiferromagnetic coupling of the magnetically permeable films in the lamination. ### Claim 12 A perpendicular magnetic recording disk comprising: a substrate; an underlayer of magnetically permeable material on the substrate; a nonmagnetic intermediate layer (IL) on the underlayer and comprising a material selected from Ru and a Ru alloy; a perpendicular magnetic recording layer comprising a first magnetic layer (MAG1 ) comprising a granular ferromagnetic alloy comprising Co, Pt and Cr and one or more oxides of one or more of Si, Ta, Ti, Nb and B on the IL; a first nucleation film (NF1 ) consisting of Ru on and in contact with MAG1 and having a thickness greater than or equal to 0.1 nm and less than or equal to 1.5 nm; a second nucleation film (NF2 ) on and in contact with NF1 and having a thickness greater than or equal to 0.2 nm and less than or equal to 1.0 nm, wherein NF2 is a discontinuous film of clusters consisting of an oxide of Ta; and a second magnetic layer (MAG2 ) ferromagnetically exchange coupled to MAG1 across NF1 and NF2, MAG2 being formed of a granular ferromagnetic alloy comprising Co, Pt and Cr and one or more oxides of one or more of Si, Ta, Ti, Nb and B on and in contact with said clusters of NF2 and on portions of NF1 , wherein MAG2 has more Pt and less Cr than MAG1 and an anisotropy field greater than the anisotropy field of MAG1. ### Claim 13 (depends on 12) The disk of claim 12 wherein NF1 is a conformal film of NF1 material on and in contact with MAG1. ### Claim 14 (depends on 12) The disk of claim 12 wherein NF1 is a discontinuous film of clusters of NF1 material on and in contact with MAG 1.